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== About Charles H. Townes<br> ==
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== About Charles H. Townes  ==
  
Article Content Goes Here...  
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[[Image:Charles Townes.jpg|thumb|left]]
  
== About the Interview  ==
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<p>[[Charles Townes|Charles H. Townes]], a 1964 [[Nobel Prize|Nobel prize]] recipient in physics, was a pioneer in the field of laser theory.&nbsp; He received the IEEE Medal of Honor in 1967 "For his significant contributions in the field of quantum electronics which have led to the maser and the [[Laser|laser]]." </p>
  
Charles H. Townes: An Interview Conducted by Frederik Nebeker, IEEE History Center, Rutgers University, New Brunswick, NJ, USA, 14-15 September 1992
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<p>Educated at Furman University, Duke University (master's degree) and the California Institute of Technology (Ph.D. in physics, 1939), Townes became a research physicist at [[Bell Labs|Bell Telephone Laboratories]] in New York, collaborating with a variety of research groups and developing a number of patents. Following his employment at Bell Labs (1939-1947), Townes joined the faculty of Columbia University, where he continued his research on the microwave spectroscope. The maser (an acronym for microwave amplification by stimulated emission of radiation) Townes developed at Columbia and patented in 1959 was the successful result of his search for a way to obtain stronger radiation with shorter wavelengths using a source other than a vacuum tube. In collaboration with his brother-in-law [[Arthur L. Schawlow|Arthur Schawlow]], Townes developed a laser, which could operate at wavelengths a thousand times shorter than masers. Laser technology, from which neither Townes nor Schawlow profited, changed the sciences of optics and electronics. </p>
  
Interview #143 for the Center for the History of Electrical Engineering, the Institute of Electrical and Electronics Engineers, Inc., and Rutgers, The State University of New Jersey
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<p>This interview covers Townes's education and research. Townes describes the work environment at Bell Labs, with particular attention to the collaboration of engineers and physicists. Analyzing the influence of World War II on Bell Labs and on scientists' goals, Townes describes research in computers' use to guide anti-aircraft guns and in radar bombing systems. While narrating his research at Columbia and his involvement in the [[IRE History 1912-1963|Institute of Radio Engineers]] and the [[IEEE History|IEEE]], Townes analyzes the interaction of physicists and engineers in the fields of radio astronomy and microwave spectroscopy. </p>
  
== Copyright Statement<br> ==
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<p>See also [[Oral-History:Charles Townes (1991)|Charles Townes Oral History (1991)]] and [[Archives:From Radar Bombing Systems to the Maser: Charles Townes as Electrical Engineer|From Radar Bombing Systems to the Maser: Charles Townes as Electrical Engineer]]. </p>
  
This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center.<br>
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== About the Interview  ==
  
Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, Rutgers - the State University, 39 Union Street, New Brunswick, NJ 08901-8538 USA. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.<br>  
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<p>Charles H. Townes: An Interview Conducted by Frederik Nebeker, IEEE History Center, New Brunswick, NJ, USA, 14-15 September 1992 </p>
  
It is recommended that this oral history be cited as follows:<br>Charles H. Townes, an oral history conducted in 1992 by Frederik Nebeker, IEEE History Center, Rutgers University, New Brunswick, NJ, USA. <br>  
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<p>Interview #143 for the Center for the History of Electrical Engineering, the Institute of Electrical and Electronics Engineers, Inc. </p>
  
== Interview ==
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== Copyright Statement ==
  
=== Studies at Cal Tech and work at Bell Labs on the eve of World War II  ===
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<p>This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center. </p>
  
'''Nebeker:'''
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<p>Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, 39 Union Street, New Brunswick, NJ 08901-8538 USA. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user. </p>
  
This is Rik Nebeker on the 14th of September 1992. I'm in Charles Townes's office in Berkeley. <br> It was in the early summer of '39 that you completed your Ph.D. at Cal Tech and were hired by Bell Labs I've heard the story of that exciting trip to Mexico that you made on the train fare that you were given. I wanted to jump to the end of that summer. One thing, is what was happening in Europe then. Do you remember, for example, the German-Soviet Nonaggression Pact in August?
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<p>It is recommended that this oral history be cited as follows: </p>
  
<br>'''Townes: '''
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<p>Charles H. Townes, an oral history conducted in 1992 by Frederik Nebeker, IEEE History Center,&nbsp;New Brunswick, NJ, USA. </p>
  
I certainly do, yes. <br>
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== Interview  ==
  
<br> '''Nebeker: '''
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=== Studies at Cal Tech and work at Bell Labs on the eve of World War II  ===
  
Did that suggest to you that war was imminent?
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<p>'''Nebeker:''' </p>
  
<br>  
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<p>This is Rik Nebeker on the 14th of September 1992. I'm in Charles Townes's office in Berkeley. It was in the early summer of '39 that you completed your Ph.D. at Cal Tech and were hired by [[Bell Labs|Bell Labs]] I've heard the story of that exciting trip to Mexico that you made on the train fare that you were given. I wanted to jump to the end of that summer. One thing, is what was happening in Europe then. Do you remember, for example, the German-Soviet Nonaggression Pact in August? </p>
  
'''Townes: '''  
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<p>'''Townes: ''' </p>
  
Well, what I remember is a little bit in hindsight now, but my impression then was what I guess everybody knows now, that Hitler was trying to shore up his possible defenses and protect himself on that front so that he could pay attention to the rest of Europe I think that's what [Chuckling] we thought it was at the time. You may have seen from these other interviews that German students were at Cal Tech and we talked with them interestedly. Most of the German students sent over had to be good Nazis, at least thought to be good Nazis, though they weren't all; some of them were pretty skeptical. Others were very strongly Nazi. We had peace marches on campus against the military-industrial complex--although that phrase wasn't used at that time--but against industrialists who were trying to get us into the war so they could sell more stuff. That was the claim. I don't think those marches were taken very seriously, but they were there. We discussed the situation and felt that we were going to have to be drawn into it somehow. It seemed very likely. Roosevelt, of course, was making moves in that direction to help. So the war clouds were all there. Various people took them with various degree of seriousness. But I think many people were quite concerned about war.  
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<p>I certainly do, yes. </p>
  
<br>  
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<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
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<p>Did that suggest to you that war was imminent? </p>
  
Were you worried that a war would disrupt your career plans?
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<p>'''Townes: ''' </p>
  
<br>  
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<p><flashmp3>143_-_townes_-_clip_1.mp3</flashmp3></p>
  
'''Townes: '''  
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<p>Well, what I remember is a little bit in hindsight now, but my impression then was what I guess everybody knows now, that Hitler was trying to shore up his possible defenses and protect himself on that front so that he could pay attention to the rest of Europe I think that's what [Chuckling] we thought it was at the time. You may have seen from these other interviews that German students were at Cal Tech and we talked with them interestedly. Most of the German students sent over had to be good Nazis, at least thought to be good Nazis, though they weren't all; some of them were pretty skeptical. Others were very strongly Nazi. We had peace marches on campus against the military-industrial complex--although that phrase wasn't used at that time--but against industrialists who were trying to get us into the war so they could sell more stuff. That was the claim. I don't think those marches were taken very seriously, but they were there. We discussed the situation and felt that we were going to have to be drawn into it somehow. It seemed very likely. Roosevelt, of course, was making moves in that direction to help. So the war clouds were all there. Various people took them with various degree of seriousness. But I think many people were quite concerned about war. </p>
  
I was more worried about whether there would be a war and what the United States would do. Obviously my career plans would be involved, but I don't remember thinking in those terms particularly. I was just worried about the general situation. <br>  
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<p>'''Nebeker: ''' </p>
  
<br>  
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<p>Were you worried that a war would disrupt your career plans? </p>
  
'''Nebeker: '''  
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<p>'''Townes: ''' </p>
  
Do you recall when you first heard of the German invasion of Poland, the 1st of September?<br>  
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<p>I was more worried about whether there would be a war and what the United States would do. Obviously my career plans would be involved, but I don't remember thinking in those terms particularly. I was just worried about the general situation. </p>
  
<br> '''Townes: '''  
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<p>'''Nebeker: ''' </p>
  
I don't recall just where I was.<br>  
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<p>Do you recall when you first heard of the German invasion of Poland, the 1st of September? </p>
  
<br> '''Nebeker: '''  
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<p>'''Townes: ''' </p>
  
You must have on your way up to New York.  
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<p>I don't recall just where I was. </p>
  
<br>  
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<p>'''Nebeker: ''' </p>
  
'''Townes: '''
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<p>You must have on your way up to New York. </p>
  
That may well be. I think I was supposed to report on the 1st of September. <br>  
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<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
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<p>That may well be. I think I was supposed to report on the 1st of September. </p>
  
I noticed that the inside cover of your first notebook at Bell Labs is dated the 12th of September, but the first entry is the 21st of September. <br>  
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<p>'''Nebeker: ''' </p>
  
<br>  
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<p>I noticed that the inside cover of your first notebook at Bell Labs is dated the 12th of September, but the first entry is the 21st of September. </p>
  
 
=== Research groups at Bell Labs, Townes's patents at Bell Labs  ===
 
=== Research groups at Bell Labs, Townes's patents at Bell Labs  ===
  
'''Townes: '''  
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<p>'''Townes: ''' </p>
  
Yes, well, when we got to Bell Labs, they had an interesting orientation process. Bell Labs, did a very good job in introducing people to the Labs. They took all the new people, about 12 or 15 around the Labs.<br>  
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<p>Yes, well, when we got to Bell Labs, they had an interesting orientation process. Bell Labs, did a very good job in introducing people to the Labs. They took all the new people, about 12 or 15 around the Labs. </p>
  
<br> '''Nebeker: '''  
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<p>'''Nebeker: ''' </p>
  
Were these all Ph.D.'s?<br>  
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<p>Were these all Ph.D.'s? </p>
  
<br> '''Townes: '''  
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<p>'''Townes: ''' </p>
  
Yes, I believe they were all Ph.D.'s, including Jim Fisk [James B. Fisk] and Bill Baker [William O. Baker] who were classmates of mine. They both became heads of the Laboratory. Jim Fisk had taught for a few years in North Carolina, and then come to the Lab. <br>  
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<p>Yes, I believe they were all Ph.D.'s, including Jim Fisk [James B. Fisk] and Bill Baker [William O. Baker] who were classmates of mine. They both became heads of the Laboratory. Jim Fisk had taught for a few years in North Carolina, and then come to the Lab. </p>
  
What the Labs did was to give us an educational briefing which probably lasted a full week. We were shown around the Labs. Buckley, who was then head of the Laboratory, talked with us about his own career and how he saw things and so on. Get all these young people and give them all a little perspective.<br>  
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<p>What the Labs did was to give us an educational briefing which probably lasted a full week. We were shown around the Labs. [[Oliver Buckley|Buckley]], who was then head of the Laboratory, talked with us about his own career and how he saw things and so on. Get all these young people and give them all a little perspective. </p>
  
<br> '''Nebeker: '''  
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<p>'''Nebeker: ''' </p>
  
Do you recall if he said anything about the possible impact of the war on Bell Labs? Bell Labs at the time was doing just a small amount of contract work for the military.<br>  
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<p>Do you recall if he said anything about the possible impact of the war on Bell Labs? Bell Labs at the time was doing just a small amount of contract work for the military. </p>
  
<br> '''Townes: '''  
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<p>'''Townes: ''' </p>
  
Right. I don't remember his saying anything, but that doesn't mean he didn't. It was, a substantial talk. Informal, but very substantial. It had a lot of parts in it, so he might well have and unless it was something quite unusual, I would not have remembered that. <br>  
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<p>Right. I don't remember his saying anything, but that doesn't mean he didn't. It was, a substantial talk. Informal, but very substantial. It had a lot of parts in it, so he might well have and unless it was something quite unusual, I would not have remembered that. </p>
  
<br> '''Nebeker: '''  
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<p>'''Nebeker: ''' </p>
  
That would be the first week or so of September?<br>  
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<p>That would be the first week or so of September? </p>
  
 +
<p>'''Townes: ''' </p>
  
'''Townes: '''
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<p>Probably, yes. That would be my guess. So that may well be why I didn't start writing anything for a while. My impression is that I was supposed to report on September 1 but that was just a round date that they had picked. We had that briefing. As you know from my other interview, Bell Laboratories was also particularly generous to me. They knew I wanted to do physics. Mervin Kelly's idea was to send me around to four different departments for three months each to get acquainted with the Laboratory. Then this would show me and show them what I was best suited for and what I should be doing. </p>
  
Probably, yes. That would be my guess. So that may well be why I didn't start writing anything for a while. My impression is that I was supposed to report on September 1 but that was just a round date that they had picked. We had that briefing. As you know from my other interview, Bell Laboratories was also particularly generous to me. They knew I wanted to do physics. Mervin Kelly's idea was to send me around to four different departments for three months each to get acquainted with the Laboratory. Then this would show me and show them what I was best suited for and what I should be doing.
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<p>'''Nebeker: ''' </p>
  
<br>'''Nebeker: '''
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<p>But there were more than four departments in physical research. </p>
  
But there were more than four departments in physical research.<br>  
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<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
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<p>Of course, there were. [Chuckling] Four was a sample, you see. I didn't know what four they were going to be, but they said four, and I said, "Well, that sounds great." As it turned out, the four that they picked were not all in physics at all. The first one was microwave tubes, which really was an engineering group. But it was a very advanced engineering group, doing fairly fundamental research work. </p>
  
Of course, there were. [Chuckling] Four was a sample, you see. I didn't know what four they were going to be, but they said four, and I said, "Well, that sounds great." As it turned out, the four that they picked were not all in physics at all. The first one was microwave tubes, which really was an engineering group. But it was a very advanced engineering group, doing fairly fundamental research work.
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<p>'''Nebeker: ''' </p>
  
<br>'''Nebeker: '''
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<p>This was [[Frederick Llewellyn|Llewellyn's]] group? </p>
  
This was Llewellyn's group?
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<p>'''Townes: ''' </p>
  
<br>  
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<p>That's right, Llewellyn's. That was my first assignment. microwaves were new and interesting, and there were plenty of basic things there. So that's how I started working with that group. I was then housed in the Graybar Building which was space they had rented in the middle of lower Manhattan because the old West Street building was full. So I was there. </p>
  
'''Townes: '''  
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<p>'''Nebeker: ''' </p>
  
That's right, Llewellyn's. That was my first assignment. microwaves were new and interesting, and there were plenty of basic things there. So that's how I started working with that group. I was then housed in the Graybar Building which was space they had rented in the middle of lower Manhattan because the old West Street building was full. So I was there.
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<p>Was it Llewellyn's group that was there? </p>
  
<br>  
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<p>'''Townes: ''' </p>
  
'''Nebeker: '''
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<p>Yes, that's right. </p>
  
Was it Llewellyn's group that was there?
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<p>'''Nebeker: ''' </p>
  
<br>  
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<p>More than that? </p>
  
'''Townes: '''  
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<p>'''Townes: ''' </p>
  
Yes, that's right.  
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<p>There were some other groups, but there were all kind of related. I think there was some microwave communication systems group or something like this. Llewellyn's group was not a large group. </p>
  
<br>'''Nebeker: '''  
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<p>'''Nebeker: ''' </p>
  
More than that?<br>  
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<p>Here is a memorandum that came out from Llewellyn at the end of that month, the 25th of September. It's considering frequency modulation. </p>
  
<br> '''Townes: '''  
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<p>'''Townes: ''' </p>
  
There were some other groups, but there were all kind of related. I think there was some microwave communication systems group or something like this. Llewellyn's group was not a large group.  
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<p>Oh, yes. Well, these are all famous names I remember very well. [Chuckling] [[E. Leon Chaffee|Chaffee]], Dietzold--Bob Dietzold, a good friend of mine. K.C. Black. Les Peterson. I thought it was Les Peterson. There was a Les Peterson I remember very well. He was a very nice person, and I learned a lot from him. </p>
  
<br>  
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<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
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<p>There's a schematic sketch on the very last page of this system. But I'm guessing that you may have come too late to be involved in this. </p>
  
Here is a memorandum that came out from Llewellyn at the end of that month, the 25th of September. It's considering frequency modulation.
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<p>'''Townes: ''' </p>
  
<br>'''Townes: '''
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<p>Yeah, I was not involved in that. </p>
  
Oh, yes. Well, these are all famous names I remember very well. [Chuckling] Chaffee, Dietzold--Bob Dietzold, a good friend of mine. K.C. Black. Les Peterson. I thought it was Les Peterson. There was a Les Peterson I remember very well. He was a very nice person, and I learned a lot from him.
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<p>'''Nebeker: ''' </p>
  
<br>'''Nebeker: '''
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<p>This was written up just a couple of weeks later. This is a later memo from Llewellyn's group. </p>
  
There's a schematic sketch on the very last page of this system. But I'm guessing that you may have come too late to be involved in this.
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<p>'''Townes: ''' </p>
  
<br>'''Townes: '''
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<p>No, I was not directly involved in that. I was put in the group, and I'm not sure that I exactly had an assignment. I think the idea was for me to just get acquainted and work with people. If I saw something to do, I would do it. Otherwise I would talk to people and try to help people, and see what happened. </p>
  
Yeah, I was not involved in that.
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<p>'''Nebeker: ''' </p>
  
<br>'''Nebeker: '''
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<p>How large was that group? </p>
  
This was written up just a couple of weeks later. This is a later memo from Llewellyn's group.
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<p>'''Townes: ''' </p>
  
<br>  
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<p>I don't know the exact size. I interacted with about ten or twelve different people. It was largely done on the basis of whom I found interesting and whom I was sitting near. I would listen to what they were doing and try to learn about it generally. There were some other groups in the building. Chuck Elmendorf, for example, was in a separate group. </p>
  
'''Townes: '''  
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<p>'''Nebeker:''' </p>
  
No, I was not directly involved in that. I was put in the group, and I'm not sure that I exactly had an assignment. I think the idea was for me to just get acquainted and work with people. If I saw something to do, I would do it. Otherwise I would talk to people and try to help people, and see what happened.<br>  
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<p>This was in Department 325, Circuit Research, with R.C. Matthies as director. Do you recall him? </p>
  
<br> '''Nebeker: '''  
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<p>'''Townes: ''' </p>
  
How large was that group?<br>  
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<p>No, I don't remember him. </p>
  
<br> '''Townes: '''  
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<p>'''Nebeker: ''' </p>
  
I don't know the exact size. I interacted with about ten or twelve different people. It was largely done on the basis of whom I found interesting and whom I was sitting near. I would listen to what they were doing and try to learn about it generally. There were some other groups in the building. Chuck Elmendorf, for example, was in a separate group. <br>  
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<p>But you were in 325D which was the designation of this. </p>
  
 +
<p>'''Townes: ''' </p>
  
'''Nebeker:'''
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<p>By now you know much more about it than I do. [Chuckling] </p>
  
This was in Department 325, Circuit Research, with R.C. Matthies as director. Do you recall him?<br>  
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<p>'''Nebeker:''' </p>
  
<br> '''Townes: '''
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<p>Evidently what you were working on in September, October, November was a project, or, as they say, Case 37010. It's listed here on these pages. The first 20 pages of the notebook, most of which we have here, are from your work with that group on this project. </p>
  
No, I don't remember him.
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<p>'''Townes: ''' </p>
  
<br>'''Nebeker: '''
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<p>Yes. </p>
  
But you were in 325D which was the designation of this.
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<p>'''Nebeker: ''' </p>
  
<br>'''Townes: '''
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<p>And I was interested to notice that in a couple of these things that you did you have them witnessed by a couple of people. That occurs first on page 7. Maybe we should look at the pages as they come and see what you recall of this work. </p>
  
By now you know much more about it than I do. [Chuckling]
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<p>'''Townes: ''' </p>
  
<br>'''Nebeker:'''
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<p>I saw a lot of Les Peterson, and Black. I'm afraid I don't recall a great deal about this. They were trying to study oscillators and potentialities of the microwaves. I was working with them, so if I got an idea, I tried to work things out. If I got an idea, I'd obviously write it down. </p>
  
Evidently what you were working on in September, October, November was a project, or, as they say, Case 37010. It's listed here on these pages. The first 20 pages of the notebook, most of which we have here, are from your work with that group on this project.
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<p>'''Nebeker: ''' </p>
  
<br>'''Townes: '''
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<p>It looks like you were taking a tube that Parker had experimented with. </p>
  
Yes.<br>  
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<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
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<p>I was trying to analyze it. </p>
  
And I was interested to notice that in a couple of these things that you did you have them witnessed by a couple of people. That occurs first on page 7. Maybe we should look at the pages as they come and see what you recall of this work.
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<p>'''Nebeker:''' </p>
  
'''<br>Townes: '''
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<p>Your own analysis? Or did you also do some other testing? </p>
  
I saw a lot of Les Peterson, and Black. I'm afraid I don't recall a great deal about this. They were trying to study oscillators and potentialities of the microwaves. I was working with them, so if I got an idea, I tried to work things out. If I got an idea, I'd obviously write it down.
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<p>'''Townes''': </p>
  
'''<br>Nebeker: '''
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<p>I must have helped do some experiments on it, too. I don't think I took the lead in experimentation this early. I was just watching other people and working with them. </p>
  
It looks like you were taking a tube that Parker had experimented with.
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<p>'''Nebeker:''' </p>
  
<br> '''Townes: '''
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<p>The effort in the electronics tube department was to get a microwave generator? </p>
  
I was trying to analyze it.
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<p>'''Townes: ''' </p>
  
<br>'''Nebeker:'''
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<p>Yeah. To get good generators. I'm afraid I don't really remember any details of this particular tube. Obviously I worked on it and obviously intentionally. Let's see, I tried to work out theory. I guess I was probably a little more theoretically inclined than some of them. But what I was trying to do was learn about it and understand it and work out theory. </p>
  
Your own analysis? Or did you also do some other testing?
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<p>'''Nebeker: ''' </p>
  
<br>'''Townes''':
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<p>I think it's very interesting that, just a month or so after arriving at Bell Labs you had come up with an idea for a high-frequency generator. Do you remember if anymore work was done on this? </p>
  
I must have helped do some experiments on it, too. I don't think I took the lead in experimentation this early. I was just watching other people and working with them.
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<p>'''Townes: ''' </p>
  
<br>'''Nebeker:'''  
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<p>Well, the only thing I clearly remember is that there was an oscillator which I kind of invented, which I thought looked promising. I did not try it out. I'd moved on to another department by then. But Jim Fisk, who was in the tube department, was asked to try it out. Jim tried it out and said it didn't work. So that was the end of that. [Chuckling] But that's the one that I remember. I think that probably went further than others and there may well have been a patent or something on it, I'm not sure. </p>
  
The effort in the electronics tube department was to get a microwave generator?
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<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
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<p>But that wasn't this particular one we're looking at here on page 7? </p>
  
Yeah. To get good generators. I'm afraid I don't really remember any details of this particular tube. Obviously I worked on it and obviously intentionally. Let's see, I tried to work out theory. I guess I was probably a little more theoretically inclined than some of them. But what I was trying to do was learn about it and understand it and work out theory.
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<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
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<p>I don't think so, no. </p>
  
I think it's very interesting that, just a month or so after arriving at Bell Labs you had come up with an idea for a high-frequency generator. Do you remember if anymore work was done on this?
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<p>'''Nebeker: ''' </p>
  
'''<br>Townes: '''
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<p>Is this part of the Bell Labs practice, that when you get an idea that might lead to something that you write it up and get someone to witness it? </p>
  
Well, the only thing I clearly remember is that there was an oscillator which I kind of invented, which I thought looked promising. I did not try it out. I'd moved on to another department by then. But Jim Fisk, who was in the tube department, was asked to try it out. Jim tried it out and said it didn't work. So that was the end of that. [Chuckling] But that's the one that I remember. I think that probably went further than others and there may well have been a patent or something on it, I'm not sure.
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<p>'''Townes: ''' </p>
  
'''<br>Nebeker: '''
+
<p><flashmp3>143_-_townes_-_clip_2.mp3</flashmp3></p>
  
But that wasn't this particular one we're looking at here on page 7?<br>  
+
<p>Yes. I was instructed about patents, you see. They're very patent conscious. So if you had an idea that you thought might be patentable, why, you witnessed it, just automatically. Anything that seemed like something really new and possibly patentable, why, you'd have it witnessed. If you took it more seriously, you might write up a memorandum and send it to the patent department. You'd send it around to other people and the patent department so that they could look at it and figure out whether they thought it was worthwhile. The patent department would decide whether they wanted to do something about it. During the Bell Labs period I had a moderate number of patents. A dozen or so. A number of them were connected with the war work. Since then I've patented practically nothing. I did patent the maser, and then I patented or rather Bell Labs patented the laser. In all of the years since then have I patented one other thing. [Chuckling] This was the generation of very high-frequency sound waves by Raman scattering. I patented that. I think that's all. At Bell Labs it was customary just to be sure that everything was reasonably covered. </p>
  
 +
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Yes. Right. </p>
  
I don't think so, no.
+
<p>'''Townes: ''' </p>
  
<br>'''Nebeker: '''
+
<p>They didn't want somebody from some competitive company stepping in and getting a patent and then blocking them from using what was developed there. They weren't so much interested in selling patents, as they were in protecting themselves to be sure they had everything covered. </p>
  
Is this part of the Bell Labs practice, that when you get an idea that might lead to something that you write it up and get someone to witness it?
+
<p>'''Nebeker: ''' </p>
  
<br>'''Townes: '''
+
<p>Looking at the following pages--I see that 9 has more analysis of the idea presented on page 7. </p>
  
Yes. I was instructed about patents, you see. They're very patent conscious. So if you had an idea that you thought might be patentable, why, you witnessed it, just automatically. Anything that seemed like something really new and possibly patentable, why, you'd have it witnessed. If you took it more seriously, you might write up a memorandum and send it to the patent department. You'd send it around to other people and the patent department so that they could look at it and figure out whether they thought it was worthwhile. The patent department would decide whether they wanted to do something about it. During the Bell Labs period I had a moderate number of patents. A dozen or so. A number of them were connected with the war work. Since then I've patented practically nothing. I did patent the maser, and then I patented or rather Bell Labs patented the laser. In all of the years since then have I patented one other thing. [Chuckling] This was the generation of very high-frequency sound waves by Raman scattering. I patented that. I think that's all. At Bell Labs it was customary just to be sure that everything was reasonably covered.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Energy exchange. Let me see now. One thing that may bear on the rapidity with which I was able to do some of this, is that I had done my thesis with W.R. Smythe who wrote a book on [[Electromagnetism|electromagnetism]] which is a standard text. He was a very tough taskmaster, and I took his course which is a kind of a course that winnowed out everybody who couldn't quite take it at Cal Tech. [Chuckling] He was proud that this would sort people out. A lot of it was problem-working. I ended up working all the problems in his new book which he was writing. So I had been very much steeped in electromagnetic theory. </p>
  
Yes. Right.
+
<p>'''Nebeker: ''' </p>
  
'''<br>Townes: '''
+
<p>So this kind of analysis was relatively easy? </p>
  
They didn't want somebody from some competitive company stepping in and getting a patent and then blocking them from using what was developed there. They weren't so much interested in selling patents, as they were in protecting themselves to be sure they had everything covered.
+
<p>'''Townes: ''' </p>
  
'''<br>Nebeker: '''
+
<p>This kind of an analysis came fairly naturally to me. That may be the reason that I could get going fairly fast here. I see here's another thing on Les Peterson. </p>
  
Looking at the following pages--I see that 9 has more analysis of the idea presented on page 7. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>You're looking at page 13. All of this looks to be further work on the apparatus described on page 7. </p>
  
Energy exchange. Let me see now. One thing that may bear on the rapidity with which I was able to do some of this, is that I had done my thesis with W.R. Smythe who wrote a book on electromagnetism which is a standard text. He was a very tough taskmaster, and I took his course which is a kind of a course that winnowed out everybody who couldn't quite take it at Cal Tech. [Chuckling] He was proud that this would sort people out. A lot of it was problem-working. I ended up working all the problems in his new book which he was writing. So I had been very much steeped in electromagnetic theory.
+
<p>'''Townes: ''' </p>
  
<br>'''Nebeker: '''
+
<p>That may be. This may well be the thing which Jim Fisk then tried out in some modification. That first version of it doesn't seem familiar to me. This one does a little bit more. This talks about field gradients and so on. Okay, now then we come to the other department. </p>
  
So this kind of analysis was relatively easy?
+
<p>'''Nebeker: ''' </p>
  
<br>'''Townes: '''
+
<p>I didn't copy the rest of the pages. So at least half of September and October and November you were working with Llewellyn's group. </p>
  
This kind of an analysis came fairly naturally to me. That may be the reason that I could get going fairly fast here. I see here's another thing on Les Peterson.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Right, yes. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
You're looking at page 13. All of this looks to be further work on the apparatus described on page 7.<br>  
+
<p>There's one other memorandum here that is from that period. I don't know if you were involved in this. It's the end of November, right about the end of your time with that group. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
That may be. This may well be the thing which Jim Fisk then tried out in some modification. That first version of it doesn't seem familiar to me. This one does a little bit more. This talks about field gradients and so on. Okay, now then we come to the other department.  
+
<p>No, I think I was not directly involved in that. I'm pretty sure I wrote up a memorandum about this kind of oscillator. </p>
  
<br>'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
I didn't copy the rest of the pages. So at least half of September and October and November you were working with Llewellyn's group.
+
<p>This is the first of the TMs that the database had for you, dated January 2nd. Do you think that is this work that's in that TM? </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>Yes. There we are. "Energy Relations of Electron Flow Through Nonuniform High-Frequency Fields." In the second part of this is the nonuniformity begins to come in. As I remember, the idea was that some electrons flow through nonuniform fields, and with that, there should be a transfer of energy from the electrons to the field. So I had worked that out and wrote a memorandum about it. Then Bell Labs had somebody try it out, and I'm not sure he was awfully enthusiastic about doing it anyhow, and it didn't seem to work and be awfully promising, so it was dropped. </p>
  
Right, yes. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>You were doing other things, and couldn't pursue it? </p>
  
There's one other memorandum here that is from that period. I don't know if you were involved in this. It's the end of November, right about the end of your time with that group.
+
<p>'''Townes: ''' </p>
  
<br>'''Townes: '''
+
<p>I was doing other things myself. </p>
  
No, I think I was not directly involved in that. I'm pretty sure I wrote up a memorandum about this kind of oscillator.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Do you recall if you were disappointed. </p>
  
This is the first of the TMs that the database had for you, dated January 2nd. Do you think that is this work that's in that TM?
+
<p>'''Townes: ''' </p>
  
<br>'''Townes: '''  
+
<p>Well, of course I was disappointed. But it wasn't a big thing. [Chuckling] I thought it was a nice idea and ought to be tried, and they claimed it didn't work. I'm sure it would have worked in some sense; but if it didn't work, you know, more or less right away, then that probably meant that it wasn't all that useful. </p>
  
Yes. There we are. "Energy Relations of Electron Flow Through Nonuniform High-Frequency Fields." In the second part of this is the nonuniformity begins to come in. As I remember, the idea was that some electrons flow through nonuniform fields, and with that, there should be a transfer of energy from the electrons to the field. So I had worked that out and wrote a memorandum about it. Then Bell Labs had somebody try it out, and I'm not sure he was awfully enthusiastic about doing it anyhow, and it didn't seem to work and be awfully promising, so it was dropped.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Was it specifically for radar that that group was trying to get a high-frequency generator? </p>
  
You were doing other things, and couldn't pursue it?
+
<p>'''Townes: ''' </p>
  
<br>'''Townes: '''
+
<p>Well, I believe that [[Bell Labs|Bell Labs]] even at that time was thinking about transmission, and primarily about transmission of telephone and television signals. </p>
  
I was doing other things myself.
+
<p>'''Nebeker: ''' </p>
  
'''<br>Nebeker: '''
+
<p>Right, we saw that one memorandum was about transmission. </p>
  
Do you recall if you were disappointed.
+
<p>'''Townes: ''' </p>
  
'''<br>Townes: '''
+
<p>Yes. They had been working in this field for some time. </p>
  
Well, of course I was disappointed. But it wasn't a big thing. [Chuckling] I thought it was a nice idea and ought to be tried, and they claimed it didn't work. I'm sure it would have worked in some sense; but if it didn't work, you know, more or less right away, then that probably meant that it wasn't all that useful.
+
<p>'''Nebeker: ''' </p>
  
<br>'''Nebeker: '''
+
<p>As early as '37 Bell Labs was working on radar for the Navy. </p>
  
Was it specifically for radar that that group was trying to get a high-frequency generator?
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>I wouldn't have known just when they started. But radar was not the primary push. </p>
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Well, I believe that Bell Labs even at that time was thinking about transmission, and primarily about transmission of telephone and television signals.
+
<p>Okay. It was just for communications? </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Right, we saw that one memorandum was about transmission.  
+
<p><flashmp3>143_-_townes_-_clip_3.mp3</flashmp3></p>
  
<br>  
+
<p>Their normal technical work involved looking at new forms of transmission. Down at Holmdel they had a group that was working largely with microwaves. There was a large amount of microwave work down at Holmdel at that time, in transmission and tubes. [[George C. Southworth|Southworth]] was becoming pretty well known for microwave work, transmission tubes, various modes and so on. He had also detected some radiation from the sun. He had taken microwave radiation from the sun. So Holmdel was a big center for fieldwork and experimental work and large-scale systems. They laid out waveguides, and some liked them and tried them out; that sort of thing. So Bell Labs was looking forward to transmission at that time, and that was what this department was primarily about. It may well be they thought some about radar, but that was not the primary push. </p>
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes. They had been working in this field for some time.<br>  
+
<p>And that wasn't what you were thinking about when you worked on this? </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
As early as '37 Bell Labs was working on radar for the Navy.  
+
<p>No, that was not primarily what I was thinking about. The radar work was probably mostly secret, and I wasn't in on the secret part. There just was no point in my being cleared for secret work since I was doing this work, which might be related but I wasn't directly involved or thinking about radar particularly. I knew Bell Labs was working on [[Cavity Magnetron|magnetrons]]. The British had brought over magnetrons, and it was basically their efforts that certainly improved the potential of magnetrons. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>I think, though, that was the following summer. </p>
  
I wouldn't have known just when they started. But radar was not the primary push. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Oh, maybe it was. Okay. You probably know the history a little more precisely than I do at this point. They brought over magnetrons, and Bell Labs started working on that right away. </p>
  
Okay. It was just for communications?
+
<p>'''Nebeker:''' </p>
  
<br>'''Townes: '''
+
<p>How was Llewellyn as a supervisor in that period? </p>
  
Their normal technical work involved looking at new forms of transmission. Down at Holmdel they had a group that was working largely with microwaves. There was a large amount of microwave work down at Holmdel at that time, in transmission and tubes. Southworth was becoming pretty well known for microwave work, transmission tubes, various modes and so on. He had also detected some radiation from the sun. He had taken microwave radiation from the sun. So Holmdel was a big center for fieldwork and experimental work and large-scale systems. They laid out waveguides, and some liked them and tried them out; that sort of thing. So Bell Labs was looking forward to transmission at that time, and that was what this department was primarily about. It may well be they thought some about radar, but that was not the primary push.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Oh, very good. Excellent. He was a very high-quality person and stimulating and very nice to me. I liked Llewellyn. I enjoyed that whole group. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
And that wasn't what you were thinking about when you worked on this?<br>  
+
<p>Did you have any regrets about moving on to another group at the end of that period? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
No, that was not primarily what I was thinking about. The radar work was probably mostly secret, and I wasn't in on the secret part. There just was no point in my being cleared for secret work since I was doing this work, which might be related but I wasn't directly involved or thinking about radar particularly. I knew Bell Labs was working on magnetrons. The British had brought over magnetrons, and it was basically their efforts that certainly improved the potential of magnetrons.<br>  
+
<p>No. I was in an exploratory mode. [Chuckling] Ready to try anything, and see what the rest of Bell Labs was like. But I liked it there. But then after I left, well, I said, "Okay, so I drop this now, and I start doing something else." It was clearly an exploratory period, and I enjoyed that, seeing what different things were being done. </p>
  
<br> '''Nebeker: '''
+
=== Magnetic material research  ===
  
I think, though, that was the following summer.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>We know that the 7th of December you were working on this other case. You moved to the next group, and that I don't have identified very well. </p>
  
Oh, maybe it was. Okay. You probably know the history a little more precisely than I do at this point. They brought over magnetrons, and Bell Labs started working on that right away.
+
<p>'''Townes:''' </p>
  
<br>'''Nebeker:'''
+
<p>I think that was a tube group. Now actually it turned out I worked only with three groups before I got this reassignment to do radar bombing work. I worked with the magnetics group under Bozorth. And I worked in the tube group. </p>
  
How was Llewellyn as a supervisor in that period?
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Was that under Davisson? </p>
  
'''Townes: '''  
+
<p>'''Townes:''' </p>
  
Oh, very good. Excellent. He was a very high-quality person and stimulating and very nice to me. I liked Llewellyn. I enjoyed that whole group.  
+
<p>I'm trying to remember. Mervin Kelly had been head of that but then had moved on up into research director or something like that at that point. Let's see. I can visualize the person who was head of that. It was not under the famous Davisson, no. No, he was in physics. The electron tube group was not in physics again. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>Well, in the April of 1940 Bell Labs phone book, you're listed as being in Department 1180 with Davisson as the head of that group. </p>
  
Did you have any regrets about moving on to another group at the end of that period?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>That was primarily a nominal thing. </p>
  
No. I was in an exploratory mode. [Chuckling] Ready to try anything, and see what the rest of Bell Labs was like. But I liked it there. But then after I left, well, I said, "Okay, so I drop this now, and I start doing something else." It was clearly an exploratory period, and I enjoyed that, seeing what different things were being done. <br>
+
<p>'''Nebeker: ''' </p>
  
=== Magnetic material research  ===
+
<p>So you were in a smaller group within that, do you think? </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
We know that the 7th of December you were working on this other case. You moved to the next group, and that I don't have identified very well.  
+
<p>Yes. I never worked with Davisson directly. I knew him well. But I worked with Bozorth who was head of the magnetic materials in the physics department--it was a solid-state group, but in the physics department--working on magnetics. Of course Bell Labs was very famous for magnetic work at that time. So that's where I was. Perhaps Bozorth reported to Davisson. </p>
  
<br>'''Townes:'''  
+
<p>'''Nebeker: ''' </p>
  
I think that was a tube group. Now actually it turned out I worked only with three groups before I got this reassignment to do radar bombing work. I worked with the magnetics group under Bozorth. And I worked in the tube group.
+
<p>We don't have an affiliation here for a long time. I mean, I assume that was the first three months you worked on your assignment. The next three months there's nothing there. Except we do know that it was this case which had the title "Fundamental Development of Electron tubes for Wire transmission Systems" that you were working on the next three months, December, January, February. Could that have been Bozorth's group? </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Nebeker: '''
+
<p>No. No, this was the development of magnetic materials. </p>
  
Was that under Davisson?
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>That was the third group you were working in? </p>
  
'''Townes:'''  
+
<p>'''Townes: ''' </p>
  
I'm trying to remember. Mervin Kelly had been head of that but then had moved on up into research director or something like that at that point. Let's see. I can visualize the person who was head of that. It was not under the famous Davisson, no. No, he was in physics. The electron tube group was not in physics again.  
+
<p>No, this was over in the old tube department. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Well, in the April of 1940 Bell Labs phone book, you're listed as being in Department 1180 with Davisson as the head of that group.  
+
<p>Maybe the name will appear in the notebook pages. </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>Yeah, yeah, maybe. Let's see. My paper might mention something like that. </p>
  
That was primarily a nominal thing.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>You were talking about the theory of cathodes sputtering paper? </p>
  
So you were in a smaller group within that, do you think?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes. Let's see my footnotes in the last part of the paper. Here's the name. Rockwood is the person I was working with then. </p>
  
Yes. I never worked with Davisson directly. I knew him well. But I worked with Bozorth who was head of the magnetic materials in the physics department--it was a solid-state group, but in the physics department--working on magnetics. Of course Bell Labs was very famous for magnetic work at that time. So that's where I was. Perhaps Bozorth reported to Davisson.
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Rockwood? </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
We don't have an affiliation here for a long time. I mean, I assume that was the first three months you worked on your assignment. The next three months there's nothing there. Except we do know that it was this case which had the title "Fundamental Development of Electron tubes for Wire transmission Systems" that you were working on the next three months, December, January, February. Could that have been Bozorth's group?
+
<p>He was not my boss, but I worked with him. As I say, I can visualize this guy, but I can't dig up his name. If you could find out who was head of the tube department at that time, I think I was officially reporting to him. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>All right. </p>
  
No. No, this was the development of magnetic materials.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>The [[Electron (or Vacuum) Tubes|vacuum tube]] department. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
That was the third group you were working in?<br>  
+
<p>I guess I don't have that department listed. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
No, this was over in the old tube department.  
+
<p>I think that probably this fellow was over in electron tubes for wire transmission, though it was just basically electron tubes. Electron emission from filaments was a very important part of any electron tube in those days. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>Okay. Pages 21 to 46. Since there are so many gaps here, 21 starts right there. This was the first of your pages from that department, the electron tube. </p>
  
Maybe the name will appear in the notebook pages.
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>What I remember about this is Rockwood had made some measurements of sputtering which really then determined the lifetime of some vacuum tube in the long run. He had made measurements of lifetime and the function of various characteristics of tubes. After again looking around and seeing what people were doing and learning some things--and I may have written a few things about other things--my primary effort then was to try to understand his experimental data. So I did a theoretical analysis. See, in three months' time it's pretty hard to get an experiment going and doing anything real. I was moderately skillful at theoretical analysis. So the way to learn things seemed to be best to go to work on the theoretical aspects of things. Rockwood probably didn't have a Ph.D. degree. He was just a good engineer who was doing experiments and finding out things. But he had not done any analysis really, and this looked like an opportunity. He had some good data, and it seemed to me an opportunity to try to understand it. </p>
  
Yeah, yeah, maybe. Let's see. My paper might mention something like that.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Is this the beginning of the work that led to the electron sputtering paper? </p>
  
You were talking about the theory of cathodes sputtering paper?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes, that's right. That's what I'm talking about. </p>
  
Yes. Let's see my footnotes in the last part of the paper. Here's the name. Rockwood is the person I was working with then.
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>And that goes for a number of pages here. </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Rockwood?
+
<p>It had to do both with the lifetime of filaments and the lifetime of these gas-discharge tubes. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Do you remember if this was regarded as useful to that group? I mean, the fact that you wrote it up as a TM and then an article suggests it was. </p>
  
He was not my boss, but I worked with him. As I say, I can visualize this guy, but I can't dig up his name. If you could find out who was head of the tube department at that time, I think I was officially reporting to him. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes, I think they appreciated it. Yeah, I think they appreciated it as the beginning of some understanding of what was going on. Hence that would allow them to engineer systems better, and to plan systems. I'm not sure really that it led to a lot of practical applications, but at least it gives some understanding of why the parameters worked out the way they did and what things one had to look for. So, yes, I think they were quite appreciative. </p>
  
All right.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Do you recall your feelings at the time? Although in a sense you're doing physics with both these first two groups, in a sense you're doing engineering. In your first case the main work was designing some generator, and here it's analyzing some experimental data. Do you recall your feelings at the time? Did you really take to this work, or did you feel that, oh, I want to be doing physics? </p>
  
The vacuum tube department.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Well, I would say I enjoyed this kind of work. It's the type of engineering which is so close to physics. It's not development of a big system or something like that, which I later did. Rather it involves trying to understand things. It's quite basic engineering, fundamental engineering, I would say. How do the electrons and fields interact, and how do surfaces interact with electrons? And so on. So that was close enough to physics that while I really didn't want to stay in those departments permanently, I felt it was quite interesting. I had no qualms about looking at that nor any lack of interest in seeing what was going on. But that was different from, building a system to put in an airplane. That's a very different kind of engineering, systems engineering. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
I guess I don't have that department listed.<br>  
+
<p>What do you recall of the second group, the electron tube group? Were you located on West Street? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I think that probably this fellow was over in electron tubes for wire transmission, though it was just basically electron tubes. Electron emission from filaments was a very important part of any electron tube in those days.  
+
<p>That's right. It was a little building right across from the main building on West Street. There's a little cross street there, and it was just over the other side of the street. It was a rather low building, a modest structure. It had been taken over by the Bell Labs from some other industry--I think I recall it being referred to as the old biscuit factory. It was just a rather large open building in which a lot of tube experimentation was going on. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>Do you recall whether there was a particular urgency for a certain type of tube or certain type of improvement that that group was interested in? </p>
  
Okay. Pages 21 to 46. Since there are so many gaps here, 21 starts right there. This was the first of your pages from that department, the electron tube.
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I think at that point with respect to radar. The urgency was there, and people were thinking about that and what could be done. But otherwise it was a question of getting longer lives and higher gains and more current density. Also one of the big pushes--although now it's gone completely out of the window with transistors--was to get gas-discharge tubes which could operate on 24 volts. You couldn't get a gas-discharge breakdown in the argon-neon combinations at that low a voltage. But they would like them to operate on 24 volts because that was a battery voltage, and the voltage that many telephones use, and they wanted to use them as switches in remote places. I was even asked specifically to look at that at some point after I'd been in this tube department for a while. I think [[Harvey Fletcher|Harvey Fletcher]] asked me would I specifically look at that. </p>
  
What I remember about this is Rockwood had made some measurements of sputtering which really then determined the lifetime of some vacuum tube in the long run. He had made measurements of lifetime and the function of various characteristics of tubes. After again looking around and seeing what people were doing and learning some things--and I may have written a few things about other things--my primary effort then was to try to understand his experimental data. So I did a theoretical analysis. See, in three months' time it's pretty hard to get an experiment going and doing anything real. I was moderately skillful at theoretical analysis. So the way to learn things seemed to be best to go to work on the theoretical aspects of things. Rockwood probably didn't have a Ph.D. degree. He was just a good engineer who was doing experiments and finding out things. But he had not done any analysis really, and this looked like an opportunity. He had some good data, and it seemed to me an opportunity to try to understand it.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>He was Director of Physical Research? </p>
  
Is this the beginning of the work that led to the electron sputtering paper?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>That's right, yes. But this was after I left. I left the other things and then was to work with Wooldridge for a while. And that was my assignment, to see if I could figure out a way of producing tubes that would break down at low voltages. </p>
  
Yes, that's right. That's what I'm talking about. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>This is later, not the third of the three? </p>
  
And that goes for a number of pages here.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes, this was later. So that was a very specific thing I was asked about. Generally, that was just in the normal course of their needs. In the normal course of their needs, they needed tubes of all kinds. But in addition to that, the radar was beginning to be quite an issue, and people were concerned about it and figuring out what could they do, and how could they do it. I was not myself involved, though. </p>
  
It had to do both with the lifetime of filaments and the lifetime of these gas-discharge tubes.
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Yeah. Of course this was in the so-called Sitzkrieg part of the war where nothing was happening in Europe. You've said earlier that you had this practice of changing your room every three months. Was that three-month period chosen to coincide with these three-month stints in different departments? [Laughter] </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Do you remember if this was regarded as useful to that group? I mean, the fact that you wrote it up as a TM and then an article suggests it was.  
+
<p>I don't know. There might have been some unconscious connection. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes, I think they appreciated it. Yeah, I think they appreciated it as the beginning of some understanding of what was going on. Hence that would allow them to engineer systems better, and to plan systems. I'm not sure really that it led to a lot of practical applications, but at least it gives some understanding of why the parameters worked out the way they did and what things one had to look for. So, yes, I think they were quite appreciative.<br>  
+
<p>This was when you moved up near Columbia University? </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Do you recall your feelings at the time? Although in a sense you're doing physics with both these first two groups, in a sense you're doing engineering. In your first case the main work was designing some generator, and here it's analyzing some experimental data. Do you recall your feelings at the time? Did you really take to this work, or did you feel that, oh, I want to be doing physics?
+
<p><flashmp3>143_-_townes_-_clip_4.mp3</flashmp3></p>
  
<br>  
+
<p>That's right. I characteristically like variety. I like change and variety. It's a lot more interesting to see something new rather than stick with something that's old. New York's an interesting place, and I debated where to live in New York. The first place obviously was Greenwich Village. That's near Bell Labs and an interesting place, and so I lived there for three months. I didn't want to just get acquainted with Greenwich Village and nothing else. So that's when I said, "Well, okay, I'll move every three months. I'll just plan to move every three months and try another place." I was a young bachelor, and there was no problem about it. I just picked up my stuff and left. </p>
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Well, I would say I enjoyed this kind of work. It's the type of engineering which is so close to physics. It's not development of a big system or something like that, which I later did. Rather it involves trying to understand things. It's quite basic engineering, fundamental engineering, I would say. How do the electrons and fields interact, and how do surfaces interact with electrons? And so on. So that was close enough to physics that while I really didn't want to stay in those departments permanently, I felt it was quite interesting. I had no qualms about looking at that nor any lack of interest in seeing what was going on. But that was different from, building a system to put in an airplane. That's a very different kind of engineering, systems engineering.
+
<p>They didn't require year-long leases in those days? </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Nebeker: '''
+
<p>No. I was renting a room by the week basically. [Laughter] I just put all my stuff in a small trunk and got in a taxi and moved to another place. I moved up near Columbia as the next stop after that. Then I moved into Midtown, and I guess about that time, then I got caught up in the war. Then I was shuffling back and forth. I got married in '41, and we lived in a number of places then as I moved back and forth from Florida, back up north again. You'd have a room or house generally. Frequently I would give up my rented quarters and then come back to a new place because I was down in Florida long enough. I could save money that way. </p>
  
What do you recall of the second group, the electron tube group? Were you located on West Street?
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Yes. How long were those periods in Florida? Do you recall? </p>
  
'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
That's right. It was a little building right across from the main building on West Street. There's a little cross street there, and it was just over the other side of the street. It was a rather low building, a modest structure. It had been taken over by the Bell Labs from some other industry--I think I recall it being referred to as the old biscuit factory. It was just a rather large open building in which a lot of tube experimentation was going on.  
+
<p>Well, they were sort of a couple of months at a time. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>That long? </p>
  
Do you recall whether there was a particular urgency for a certain type of tube or certain type of improvement that that group was interested in?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Something like that. </p>
  
I think at that point with respect to radar. The urgency was there, and people were thinking about that and what could be done. But otherwise it was a question of getting longer lives and higher gains and more current density. Also one of the big pushes--although now it's gone completely out of the window with transistors--was to get gas-discharge tubes which could operate on 24 volts. You couldn't get a gas-discharge breakdown in the argon-neon combinations at that low a voltage. But they would like them to operate on 24 volts because that was a battery voltage, and the voltage that many telephones use, and they wanted to use them as switches in remote places. I was even asked specifically to look at that at some point after I'd been in this tube department for a while. I think Harvey Fletcher asked me would I specifically look at that. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Okay. So is there any more that you want to say about that second group that you worked with? </p>
  
He was Director of Physical Research?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>No, I don't think so. I think maybe I've covered that. </p>
  
That's right, yes. But this was after I left. I left the other things and then was to work with Wooldridge for a while. And that was my assignment, to see if I could figure out a way of producing tubes that would break down at low voltages. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Then it must have been in March, in '40 that you moved to a third group because the notebook records this as a different case. It's development of magnetic materials. </p>
  
This is later, not the third of the three?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Magnetic materials. Yes. </p>
  
Yes, this was later. So that was a very specific thing I was asked about. Generally, that was just in the normal course of their needs. In the normal course of their needs, they needed tubes of all kinds. But in addition to that, the radar was beginning to be quite an issue, and people were concerned about it and figuring out what could they do, and how could they do it. I was not myself involved, though.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>And this is Bozorth? </p>
  
Yeah. Of course this was in the so-called Sitzkrieg part of the war where nothing was happening in Europe. You've said earlier that you had this practice of changing your room every three months. Was that three-month period chosen to coincide with these three-month stints in different departments? [Laughter]<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Bozorth, right. Now Bozorth was specifically a physicist, and I worked fairly closely with him. He headed the group. I don't think I did any particularly creative thing there. I was mainly learning. [Change to Side B of Tape] The magnetics department was quite a sophisticated department since Bell Labs was pretty ahead of the game in magnetic materials at that point. I learned a good deal from it. I was not thrilled by it because it seemed to me a little confining and a little limited in terms of scope. But on the other hand, it was interesting so far as it went, and a high-quality department. </p>
  
I don't know. There might have been some unconscious connection. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I only have one page, it looks like, from this case called "Development of Magnetic Materials," page 48 there. This is it. When I didn't copy pages it was because there were mainly just numbers there. There you see bridge measurements on inductance. Looks like you were taking measurements yourself? </p>
  
This was when you moved up near Columbia University?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes, I was taking measurements. I may have had some idea about laminations and tried to do something there. I remember a man named [[John M. Cioffi‎|Cioffi]]. Cioffi was working in that group at the time. Then there was still present a fairly elderly gentleman who had first discovered this very highly, very easily, magnetized material. I forget what it's called. [Chuckling] This was Bell Labs's great breakthrough. Anyhow, he was still around, and he was a grand old man, and he just sat there smoking cigars, I remember. Well, he'd made a great breakthrough, and that was it. </p>
  
That's right. I characteristically like variety. I like change and variety. It's a lot more interesting to see something new rather than stick with something that's old. New York's an interesting place, and I debated where to live in New York. The first place obviously was Greenwich Village. That's near Bell Labs and an interesting place, and so I lived there for three months. I didn't want to just get acquainted with Greenwich Village and nothing else. So that's when I said, "Well, okay, I'll move every three months. I'll just plan to move every three months and try another place." I was a young bachelor, and there was no problem about it. I just picked up my stuff and left.<br>
+
=== The effect of war on Bell Labs, 1940  ===
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
They didn't require year-long leases in those days?  
+
<p>I know once the war started the pace of work at Bell Labs was intense with a lot of overtime and short vacations and so on. What do you recall of this period? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
No. I was renting a room by the week basically. [Laughter] I just put all my stuff in a small trunk and got in a taxi and moved to another place. I moved up near Columbia as the next stop after that. Then I moved into Midtown, and I guess about that time, then I got caught up in the war. Then I was shuffling back and forth. I got married in '41, and we lived in a number of places then as I moved back and forth from Florida, back up north again. You'd have a room or house generally. Frequently I would give up my rented quarters and then come back to a new place because I was down in Florida long enough. I could save money that way.<br>  
+
<p><flashmp3>143_-_townes_-_clip_5.mp3</flashmp3></p>
  
<br> '''Nebeker: '''
+
<p>Well, it was a very pleasant period for me. For one thing, I had some money. I was paid $3,016 a year; I remember it very well. It seemed like a lot of money to me. As a student I had lived on about one fifth of that. Certainly I had some money, and I was in New York, and I was making a lot of new friends, and we'd all go out to lunch in Greenwich Village. They knew all the good restaurants. I was exploring New York. At some point I was taking music lessons up at Juilliard, too. So, while I worked hard, it was not something that I had to do at nights and Saturdays. I could work more or less at what would be a normal pace. It was a very pleasant time. I made a lot of new friends, and met people. </p>
  
Yes. How long were those periods in Florida? Do you recall?
+
<p>[[William Shockley|Bill Shockley]] was there, and Dean Wooldridge and Jim Fisk and a lot of other good friends that I've known for a long time. Plus a number of these engineers that I enjoyed very much. Bozorth was very kind to me, and [[Frederick Llewellyn|Llewellyn]]. Les Peterson. I got to know a different group of people. Given my exploratory instincts, I found that very interesting. They were really quite sharp people and they also knew something about political things. I remember one engineer who interested me particularly. I believe he had a Czech background. He had a brother who visited in the Soviet Union and heard some of the Stalin trials, of that period, and swore that they were real, that these people would confess that sure enough they'd been betraying their country and so on. It was convincing and so this was a great plus for the Communist cause, you see, that these people admitted they had been doing terrible things against the government. His brother had been there and witnessed it and it was real. Along with the Nazi crowd this was one of the things that was being discussed. How real was this, and what was Communism, and what wasn't. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Of course it was also in April of 1940 that the Blitzkrieg overwhelmed the Low Countries, and France was forced out of the war. Do you remember that month? </p>
  
Well, they were sort of a couple of months at a time.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I remember the invasion, but I don't place it in time or exactly what I was doing during that time. </p>
  
That long?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I was just wondering if you recall your feelings. It must have been a surprise to people how quickly France fell, and it seemed that England was almost knocked out of the war. </p>
  
Something like that. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p><flashmp3>143_-_townes_-_clip_6.mp3</flashmp3></p>
  
Okay. So is there any more that you want to say about that second group that you worked with?<br>  
+
<p>That's when people really began to get very worried that we were going to have to be involved somehow. There was talk about it all along. But nevertheless that of course made it much more severe. I know the Bell Labs people were talking about what could they do to help besides getting ready and trying to help the British. They were looking for places where they could pitch in. They were very, very good in acoustics because Harvey Fletcher was an acoustics man. Then somebody under him was also very prominent in acoustics. They'd gone to the Navy and said, "We're experts in acoustics. We know that you're very much involved in the submarine problem, and can you think of anything that we can do to help?" This was before we got into the war and the Navy told them, no. We've got very good people, and everything's under control. Thank you very much, but we think everything's taken care of. Then some ships began to be sunk and they were called in. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
No, I don't think so. I think maybe I've covered that.<br>  
+
<p>It may also be that the attempts to put technology to work in World War I hadn't been, except in a few cases, as great a success as they were in World War II. So the military services weren't as willing to accept. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Then it must have been in March, in '40 that you moved to a third group because the notebook records this as a different case. It's development of magnetic materials.  
+
<p>I think that's right. I think it was the chemists who came through in World War I. Not so much physics and engineering. </p>
  
<br>
+
=== Electron physics research  ===
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Magnetic materials. Yes.  
+
<p>Then there's sort of a mystery case here that you worked on. Its number is 35887. It's the next page there beginning in mid-April of '40. You worked for quite some time on this case. That number isn't in the Bell Labs database now. Maybe you can tell what this work is by looking at some of these pages. On page 62 you're calculating the probability of ion capture and an ion capturing an electron approaching a metallic surface. That sounds like electron tubes. </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Nebeker: '''
+
<p>Yes, I think I know what this is, but let me see. Let me just check through this a little bit more. </p>
  
And this is Bozorth?
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>It doesn't look like this is still magnetics work. </p>
  
'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Bozorth, right. Now Bozorth was specifically a physicist, and I worked fairly closely with him. He headed the group. I don't think I did any particularly creative thing there. I was mainly learning. [Change to Side B of Tape] The magnetics department was quite a sophisticated department since Bell Labs was pretty ahead of the game in magnetic materials at that point. I learned a good deal from it. I was not thrilled by it because it seemed to me a little confining and a little limited in terms of scope. But on the other hand, it was interesting so far as it went, and a high-quality department.  
+
<p>No, no, it's not. I think I know what it is. I'm just reviewing it. </p>
  
 +
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>Pages 57 to 120 in this notebook are apparently part of Case 35887. </p>
  
I only have one page, it looks like, from this case called "Development of Magnetic Materials," page 48 there. This is it. When I didn't copy pages it was because there were mainly just numbers there. There you see bridge measurements on inductance. Looks like you were taking measurements yourself?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes. Okay. My memory comes back to me now. I had not realized that I had spent as much time on this. I remember working on this only rather a short time, but apparently it was a much longer time than I realized. I know I left Bozorth's group to start working with Wooldridge. This was work with him. Wooldridge was then doing work in electron physics. He worked on secondary emission, for example, from surfaces. So I was assigned to work with him. This was part of the thing that I mentioned to you, that I should look into the possibility of getting gas-discharge tubes which would break down at much lower voltages. </p>
  
Yes, I was taking measurements. I may have had some idea about laminations and tried to do something there. I remember a man named Cioffi. Cioffi was working in that group at the time. Then there was still present a fairly elderly gentleman who had first discovered this very highly, very easily, magnetized material. I forget what it's called. [Chuckling] This was Bell Labs's great breakthrough. Anyhow, he was still around, and he was a grand old man, and he just sat there smoking cigars, I remember. Well, he'd made a great breakthrough, and that was it.
+
<p>'''Nebeker: ''' </p>
  
=== The effect of war on Bell Labs, 1940  ===
+
<p>At 24 volts? </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I know once the war started the pace of work at Bell Labs was intense with a lot of overtime and short vacations and so on. What do you recall of this period?<br>  
+
<p>Right. So then I began studying fundamental mechanisms in discharges. I had not recognized at all that it lasted so long. [Chuckling] My recollection is that it was a relatively short period. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Well, it was a very pleasant period for me. For one thing, I had some money. I was paid $3,016 a year; I remember it very well. It seemed like a lot of money to me. As a student I had lived on about one fifth of that. Certainly I had some money, and I was in New York, and I was making a lot of new friends, and we'd all go out to lunch in Greenwich Village. They knew all the good restaurants. I was exploring New York. At some point I was taking music lessons up at Juilliard, too. So, while I worked hard, it was not something that I had to do at nights and Saturdays. I could work more or less at what would be a normal pace. It was a very pleasant time. I made a lot of new friends, and met people. <br>  
+
<p>Right. Page 121 is the first with this new case number [37641]. Just the last few pages of this notebook. But it looks like similar work, doesn't it? </p>
  
 +
<p>'''Townes: ''' </p>
  
 +
<p>Yes, it does. I think it's closely related work. And why it's a new case number, I don't know. </p>
  
Bill Shockley was there, and Dean Wooldridge and Jim Fisk and a lot of other good friends that I've known for a long time. Plus a number of these engineers that I enjoyed very much. Bozorth was very kind to me, and Llewellyn. Les Peterson. I got to know a different group of people. Given my exploratory instincts, I found that very interesting. They were really quite sharp people and they also knew something about political things. I remember one engineer who interested me particularly. I believe he had a Czech background. He had a brother who visited in the Soviet Union and heard some of the Stalin trials, of that period, and swore that they were real, that these people would confess that sure enough they'd been betraying their country and so on. It was convincing and so this was a great plus for the Communist cause, you see, that these people admitted they had been doing terrible things against the government. His brother had been there and witnessed it and it was real. Along with the Nazi crowd this was one of the things that was being discussed. How real was this, and what was Communism, and what wasn't.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>So this was still from, it looks like, mid-April until the end of the year anyway. If we include the work on case 37641 this makes eleven months for this work. </p>
  
Of course it was also in April of 1940 that the Blitzkrieg overwhelmed the Low Countries, and France was forced out of the war. Do you remember that month?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Now that surprises me, though. </p>
  
I remember the invasion, but I don't place it in time or exactly what I was doing during that time.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I mean, you may have been working on something concurrently, although there's not a notebook to show that. </p>
  
I was just wondering if you recall your feelings. It must have been a surprise to people how quickly France fell, and it seemed that England was almost knocked out of the war.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Yes, now let me see. Well, you see here is the 5th of March 1940 [37063-2]. That's magnetics. Here is May 31st. </p>
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
That's when people really began to get very worried that we were going to have to be involved somehow. There was talk about it all along. But nevertheless that of course made it much more severe. I know the Bell Labs people were talking about what could they do to help besides getting ready and trying to help the British. They were looking for places where they could pitch in. They were very, very good in acoustics because Harvey Fletcher was an acoustics man. Then somebody under him was also very prominent in acoustics. They'd gone to the Navy and said, "We're experts in acoustics. We know that you're very much involved in the submarine problem, and can you think of anything that we can do to help?" This was before we got into the war and the Navy told them, no. We've got very good people, and everything's under control. Thank you very much, but we think everything's taken care of. Then some ships began to be sunk and they were called in. <br>  
+
<p>Right. Unfortunately there were two pages in between there that I didn't copy, but the first date on the new case number [35887] was the 17th of April. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
It may also be that the attempts to put technology to work in World War I hadn't been, except in a few cases, as great a success as they were in World War II. So the military services weren't as willing to accept.  
+
<p>Oh, 17th of April. Okay. That's what I thought. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
I think that's right. I think it was the chemists who came through in World War I. Not so much physics and engineering.  
+
<p>And then you're working on this case until the end of November [35887], and then there don't seem to be entries for December of '40. And then the early part of '41 you're working on this closely related case, evidently. </p>
  
<br>
+
<p>'''Townes: ''' </p>
  
=== Electron physics research  ===
+
<p>Let me see when that paper was submitted. I got the idea for that paper from Rockwood's results when I was with his department. But the paper was written after I was working with Wooldridge. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Then there's sort of a mystery case here that you worked on. Its number is 35887. It's the next page there beginning in mid-April of '40. You worked for quite some time on this case. That number isn't in the Bell Labs database now. Maybe you can tell what this work is by looking at some of these pages. On page 62 you're calculating the probability of ion capture and an ion capturing an electron approaching a metallic surface. That sounds like electron tubes.
+
<p>Could it be that's what you were doing in December of '40? </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>That may well be. </p>
  
Yes, I think I know what this is, but let me see. Let me just check through this a little bit more. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Because the technical memorandum was dated January of '41. </p>
  
It doesn't look like this is still magnetics work.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes. Well, I see I finally published it. But I sent it in in '44 so that it was a long delay before I sent it in. </p>
  
No, no, it's not. I think I know what it is. I'm just reviewing it.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>But the TM is dated January of '41. </p>
  
Pages 57 to 120 in this notebook are apparently part of Case 35887. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes. I remember Wooldridge was my boss at the time that I was writing it. The technical memorandum was just signed by me, was it? </p>
  
Yes. Okay. My memory comes back to me now. I had not realized that I had spent as much time on this. I remember working on this only rather a short time, but apparently it was a much longer time than I realized. I know I left Bozorth's group to start working with Wooldridge. This was work with him. Wooldridge was then doing work in electron physics. He worked on secondary emission, for example, from surfaces. So I was assigned to work with him. This was part of the thing that I mentioned to you, that I should look into the possibility of getting gas-discharge tubes which would break down at much lower voltages.
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>I haven't seen a copy of it, but it is in your name alone. </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
At 24 volts?<br>  
+
<p>It's funny the things you remember. But what I remember is that I was going to have Rockwood on the memorandum, or at least on the paper, and I had initially done that. And Wooldridge said, "Well, now look, Rockwood hasn't really done anything about this. You're being unfair to yourself," and so on. [Chuckling] I said, "Well, you know, I used his data." "No, you shouldn't put his name on it." I remember that, and obviously I was reporting to Wooldridge at the time. I remember a few things here and there, but I had no idea I'd worked on this as long as I did. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Right. So then I began studying fundamental mechanisms in discharges. I had not recognized at all that it lasted so long. [Chuckling] My recollection is that it was a relatively short period.<br>  
+
<p>Was this work that is on these pages here related to that paper, that TM? </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Right. Page 121 is the first with this new case number [37641]. Just the last few pages of this notebook. But it looks like similar work, doesn't it?<br>  
+
<p>Yes and no. The primary object of this work was to try to understand the breakdown voltage in tubes. You can see discussions and experiments and so on of looking at ways of maybe studying breakdown and maybe making breakdown at lower voltage. That was the primary object. However, I was writing the paper in part during this time. When did the memorandum come out? </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes, it does. I think it's closely related work. And why it's a new case number, I don't know. <br>  
+
<p>It's dated 6th of January '41. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
So this was still from, it looks like, mid-April until the end of the year anyway. If we include the work on case 37641 this makes eleven months for this work.<br>  
+
<p>Sixth of January '41. I was writing up a paper for publication using that as a base at some point while I was with Wooldridge. The paper was actually submitted quite a while later. Let me see if I can reconstruct this. My assignment with Bozorth may well have been cut short a little bit. My fourth assignment was to work with Wooldridge, which was again directly in the physics department. I was asked if I would look into the possibility of getting this low voltage. How soon that was after I started working with Wooldridge, I don't know, but probably fairly soon. So I was working in that field most of this time until then this defense problem came along. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Now that surprises me, though. <br>  
+
<p>Right. That starts a new notebook which is dated 28 February of '41. First entry was the 3rd of March. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I mean, you may have been working on something concurrently, although there's not a notebook to show that.<br>  
+
<p>That event I remember well. I think for one thing I never made very much progress in this discharge tube business. Obviously I was doing some work and looking at things, but I never had any great success, and maybe that's one of the reasons I don't remember it so well. [Chuckling] </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes, now let me see. Well, you see here is the 5th of March 1940 [37063-2]. That's magnetics. Here is May 31st.<br>  
+
<p>How was that group, and how was Wooldridge to work for? </p>
  
<br> '''Nebeker: '''
+
=== Bell Labs seminars on physics research  ===
  
Right. Unfortunately there were two pages in between there that I didn't copy, but the first date on the new case number [35887] was the 17th of April.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Oh, Wooldridge was excellent. He is a very intelligent person and sensible. He was doing good work himself. He gave me pretty complete freedom, and I would tell him what I was doing every once in a while. I remember interactions with Wooldridge very pleasantly. It was not a close interaction. He was just my supervisor. He was highly thought of in the Lab. </p>
  
Oh, 17th of April. Okay. That's what I thought.<br>  
+
<p><flashmp3>143_-_townes_-_clip_7.mp3</flashmp3></p>
  
<br> '''Nebeker: '''
+
<p>I can't pinpoint the starting time but somewhere along in there Mervin Kelly had another idea which was very unusual for an industrial firm at that time. That was to have a seminar so that the people in the Lab could keep up with some of the latest things going on and continue to get educated. He also started what became known as Kelly College, which was a way of letting the technicians and others in the Lab who'd come in without degrees get a degree which was also a very useful function. The seminar was, I think, quite unheard of in industry at that time. He picked out a certain number of people--there were about eight or ten of us--who were to meet together once a week and basically have an afternoon off to talk about some aspect of physics or related matters. We could do anything we wanted to. We could read scientific papers, we could invite somebody to come and talk, we could read through important new books or something like this. Whatever we wanted. And the Laboratory provided tea and cookies, [Chuckling] which was again quite unheard of at that time. </p>
  
And then you're working on this case until the end of November [35887], and then there don't seem to be entries for December of '40. And then the early part of '41 you're working on this closely related case, evidently. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Was this Kelly's idea that the latest results in physics had relevance to the engineering? </p>
  
Let me see when that paper was submitted. I got the idea for that paper from Rockwood's results when I was with his department. But the paper was written after I was working with Wooldridge.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Yes, and that his people ought to be kept up to date. He had brought in--solid-state physicists, too, feeling that, well, solid-state certainly had something to do with the Bell Laboratories' business. I think part of this time when I was also working on vacuum tubes, I also looked at sputtering on switches a little bit. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Could it be that's what you were doing in December of '40?<br>  
+
<p>I notice sputtering is listed a couple of times in these pages. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
That may well be.<br>  
+
<p>I looked at the wear of relay switches a little bit. I don't think I made any headway on it. But that was one solid-state problem obviously. [Chuckling] Electroconductivity through wires was another one. [[Transistors|Transistors]] was another one which was to come along later and was not then in view. Certainly thermistors was another one. Thermistors were known at that time, as they had been invented by a chap there at Bell Labs. So Kelly as quite aware that solids might really make a difference to the business. He felt, that solid-state physics was a new field and he ought to hire some solid-state physicists, which he did. He hired Shockley who came in just a few years before I did. Foster Nix was another solid-state physicist there who was in our seminar group. And Dean Wooldridge, Jim Fisk and Walter Brattain were part of the seminar. That was a very stimulating group within the Lab. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Because the technical memorandum was dated January of '41.
+
<p>Was this physics seminar especially directed to solid-state physics? </p>
  
'''<br>Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes. Well, I see I finally published it. But I sent it in in '44 so that it was a long delay before I sent it in.  
+
<p>No, no. It was just anything we wanted to discuss. Anything we wanted to take up. We generally took up things that were close to our own work or things that might be close to our work, so they were frequently related. But they were just supposed to be the latest things that we found interesting and could take some time off to work on. That was going on sometime along in here and continued into the time after the war. It was so successful and worthwhile that similar things were being done even after the war. I remember we eventually studied Pauling's book on chemical bonds. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
But the TM is dated January of '41. <br>  
+
<p>It was throughout this period a group of a dozen or so? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes. I remember Wooldridge was my boss at the time that I was writing it. The technical memorandum was just signed by me, was it?<br>  
+
<p>Yes. About eight to twelve people. Something like that. A lot of the most active research people. But Kelly had picked them out himself as to who was going to be involved. [Laughter] </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
I haven't seen a copy of it, but it is in your name alone.<br>  
+
<p>You felt privileged there, I imagine. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
It's funny the things you remember. But what I remember is that I was going to have Rockwood on the memorandum, or at least on the paper, and I had initially done that. And Wooldridge said, "Well, now look, Rockwood hasn't really done anything about this. You're being unfair to yourself," and so on. [Chuckling] I said, "Well, you know, I used his data." "No, you shouldn't put his name on it." I remember that, and obviously I was reporting to Wooldridge at the time. I remember a few things here and there, but I had no idea I'd worked on this as long as I did.<br>  
+
<p>I felt privileged to be in that group, and it was a privilege. A very good group of people. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Was this work that is on these pages here related to that paper, that TM?<br>  
+
<p>I'm puzzled by this long period with Wooldridge's group. It looks as if you did your little apprenticeship in different departments and then settled into that group. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes and no. The primary object of this work was to try to understand the breakdown voltage in tubes. You can see discussions and experiments and so on of looking at ways of maybe studying breakdown and maybe making breakdown at lower voltage. That was the primary object. However, I was writing the paper in part during this time. When did the memorandum come out? <br>  
+
<p>Well, I think that's right. I think maybe this was sort of supposed to be my fourth group, but it was a group that I was going to be more or less permanently attached to. I found it quite congenial, and I felt, yes, sure, that's a very reasonable thing for me to do. This applied physics to understand ionization and surface interaction of electrons and things of this type. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
It's dated 6th of January '41.
+
<p>That was congenial to you, that kind of work? </p>
  
<br>'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Sixth of January '41. I was writing up a paper for publication using that as a base at some point while I was with Wooldridge. The paper was actually submitted quite a while later. Let me see if I can reconstruct this. My assignment with Bozorth may well have been cut short a little bit. My fourth assignment was to work with Wooldridge, which was again directly in the physics department. I was asked if I would look into the possibility of getting this low voltage. How soon that was after I started working with Wooldridge, I don't know, but probably fairly soon. So I was working in that field most of this time until then this defense problem came along.<br>  
+
<p>Yes, I found that fairly congenial. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Right. That starts a new notebook which is dated 28 February of '41. First entry was the 3rd of March. <br>  
+
<p>You imagined that you'd be continuing that kind of work? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
That event I remember well. I think for one thing I never made very much progress in this discharge tube business. Obviously I was doing some work and looking at things, but I never had any great success, and maybe that's one of the reasons I don't remember it so well. [Chuckling]<br>  
+
<p>So far as I knew, I would continue that for a while. So I went about it in a fairly extensive way. I had not remembered that it had lasted this long actually. I guess that's because there were no crises or anything; I just rolled along. [Chuckling] I think also I didn't have any great success. But then it was kind of a longer-term thing. These other things I just dipped into and I wanted to do something, so I did some analyses. This I was approaching on a kind of a longer-term basis. </p>
  
<br> '''Nebeker: '''
+
=== U.S. decisions about involvement in World War II  ===
  
How was that group, and how was Wooldridge to work for? <br> <br>  
+
<p>'''Nebeker: ''' </p>
  
=== Bell Labs seminars on physics research  ===
+
<p>Do you recall the political-military situation in this period? There was something of a stand-off with Hitler unable to invade England. Of course this is before the invasion of Russia in June of '41. But I think throughout this period the United States was becoming more and more involved with Lend-Lease. Do you recall this period? </p>
  
'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Oh, Wooldridge was excellent. He is a very intelligent person and sensible. He was doing good work himself. He gave me pretty complete freedom, and I would tell him what I was doing every once in a while. I remember interactions with Wooldridge very pleasantly. It was not a close interaction. He was just my supervisor. He was highly thought of in the Lab. I can't pinpoint the starting time but somewhere along in there Mervin Kelly had another idea which was very unusual for an industrial firm at that time. That was to have a seminar so that the people in the Lab could keep up with some of the latest things going on and continue to get educated. He also started what became known as Kelly College, which was a way of letting the technicians and others in the Lab who'd come in without degrees get a degree which was also a very useful function. The seminar was, I think, quite unheard of in industry at that time. He picked out a certain number of people--there were about eight or ten of us--who were to meet together once a week and basically have an afternoon off to talk about some aspect of physics or related matters. We could do anything we wanted to. We could read scientific papers, we could invite somebody to come and talk, we could read through important new books or something like this. Whatever we wanted. And the Laboratory provided tea and cookies, [Chuckling] which was again quite unheard of at that time. <br>  
+
<p>Yes, I do in general. There was a lot of discussion about what was going to happen and should we do this or should we do that? And what Roosevelt was doing. Roosevelt obviously was trying very hard to help the British, and one could argue that he was trying to find ways in which we could get involved gracefully because he felt we had to be involved. But a number of people opposed that. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Was this Kelly's idea that the latest results in physics had relevance to the engineering?  
+
<p>What was your feeling at the time? </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>I felt it was likely, but still kind of unthinkable. Kind of unthinkable that we should be in the war. </p>
  
Yes, and that his people ought to be kept up to date. He had brought in--solid-state physicists, too, feeling that, well, solid-state certainly had something to do with the Bell Laboratories' business. I think part of this time when I was also working on vacuum tubes, I also looked at sputtering on switches a little bit.
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Did you think the United States should do all it could to stay out of the war? </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I notice sputtering is listed a couple of times in these pages. <br>  
+
<p><flashmp3>143_-_townes_-_clip_8.mp3</flashmp3></p>
  
<br> '''Townes: '''  
+
<p>I thought we ought to do as much as we could reasonably to help but not overtly enter the war unless something else happened. That was my feeling. If England had been attacked at that point in a way which was completely threatening to it, I don't know what I would have said. It probably would have been too late for us to get going even. [Chuckling] I was not exactly opposed to doing something overt. On the other hand, I was not highly in favor of it either. I didn't see a way for us to get involved in any very clean way. Even though we might help them in minor ways, we might help out in some particular attack or something, but how could we reasonably get involved? In a sense it was very lucky that the Japanese attacked the way they did, and that swung the whole nation around. Because I think a lot of people were troubled by the same thing: Why should we get involved in Europe's troubles again? Is there a real reason? Well, yes, there's a kind of a reason, but there's no occasion. What could you back it up with? </p>
  
I looked at the wear of relay switches a little bit. I don't think I made any headway on it. But that was one solid-state problem obviously. [Chuckling] Electroconductivity through wires was another one. Transistors was another one which was to come along later and was not then in view. Certainly thermistors was another one. Thermistors were known at that time, as they had been invented by a chap there at Bell Labs. So Kelly as quite aware that solids might really make a difference to the business. He felt, that solid-state physics was a new field and he ought to hire some solid-state physicists, which he did. He hired Shockley who came in just a few years before I did. Foster Nix was another solid-state physicist there who was in our seminar group. And Dean Wooldridge, Jim Fisk and Walter Brattain were part of the seminar. That was a very stimulating group within the Lab. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Well, it could have been the same sort of thing as happened in World War I. That is, more German U-boat attacks with escalating tension. </p>
  
Was this physics seminar especially directed to solid-state physics?
+
=== Secret research on computers' use for anti-aircraft guns  ===
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>There might have been, and people were thinking of that, and those kinds of things were happening. The Germans were being pretty aggressive, and those kinds of things were happening, and they were talking about what could get us in again. But mostly I think everybody wanted to help but just didn't feel there was a good reason for actually jumping in. There was, again, an increasing interest in the technology. I think by then Lovell's group must have started, and that was highly secret. </p>
  
No, no. It was just anything we wanted to discuss. Anything we wanted to take up. We generally took up things that were close to our own work or things that might be close to our work, so they were frequently related. But they were just supposed to be the latest things that we found interesting and could take some time off to work on. That was going on sometime along in here and continued into the time after the war. It was so successful and worthwhile that similar things were being done even after the war. I remember we eventually studied Pauling's book on chemical bonds. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Whose group? </p>
  
It was throughout this period a group of a dozen or so?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p><flashmp3>143_-_townes_-_clip_9.mp3</flashmp3></p>
  
Yes. About eight to twelve people. Something like that. A lot of the most active research people. But Kelly had picked them out himself as to who was going to be involved. [Laughter]
+
<p>Lovell's. He had the idea of doing anti-aircraft aiming using analog computers, electronic computers. The whole thing started by his somehow getting interested in--and maybe he'd done something on this before--using potentiometers for computing. Basically you rotate a potentiometer at a given place, and you get a given voltage, and so you vary voltages around in an electromechanical computing system. It's completely analog. </p>
  
<br> '''Nebeker: '''
+
<p>That led him to suggest using this for anti-aircraft guns. Anti-aircraft, that was a very hot topic at that time because the Germans were bombing Great Britain. So he was immediately gotten started on that. So he felt he had an idea and wanted to do it. It was a new idea. Everything else was mechanical and optical, and here he's going to put in some electronics and some electronic computing, as primitive as it was, and it seemed like an advance. So he made this anti-aircraft system, and it worked. Now I didn't know a lot about it. </p>
  
You felt privileged there, I imagine.
+
<p>'''Nebeker: ''' </p>
  
'''<br>Townes: '''
+
<p>Where was that work being done? </p>
  
I felt privileged to be in that group, and it was a privilege. A very good group of people. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>That was at Bell Labs. </p>
  
I'm puzzled by this long period with Wooldridge's group. It looks as if you did your little apprenticeship in different departments and then settled into that group.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>West Street? </p>
  
Well, I think that's right. I think maybe this was sort of supposed to be my fourth group, but it was a group that I was going to be more or less permanently attached to. I found it quite congenial, and I felt, yes, sure, that's a very reasonable thing for me to do. This applied physics to understand ionization and surface interaction of electrons and things of this type.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Bell Labs, West Street. I realized that was going on, I knew some of the people who were doing it, and so I knew sort of in general what they were doing. But it was secret, and I didn't have much to do with it. The computing business, of course, was very different then. George Stibitz was a mathematician; you may know about him. I remember very well his rolling around a relay rack. This was after I was over in New Jersey at Bell Labs; it was during the war. He was rolling around a relay rack to show people how you could compute with relays. He said, "Look, you've got to do it digitally. Otherwise you'll never get any precision. You have to do it digitally." Well, he was doing it with relays. [Chuckling] A rack full of mechanical things. [Laughter] </p>
  
That was congenial to you, that kind of work?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Doing simple addition. </p>
  
Yes, I found that fairly congenial. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>People were not highly impressed with that. [Laughter] They weren't highly impressed, but, in principle you certainly can get more accuracy. We were doing a similar thing with analog computers, basically potentiometers. Lovell had the idea of shaping a potentiometer so that for a given angle you could get a more arbitrary function. You wound the potentiometer on a card of varying height so that the resistance varied, not linearly but with some other kind of functional form. </p>
  
You imagined that you'd be continuing that kind of work?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Right. So it's something like a function generator? </p>
  
So far as I knew, I would continue that for a while. So I went about it in a fairly extensive way. I had not remembered that it had lasted this long actually. I guess that's because there were no crises or anything; I just rolled along. [Chuckling] I think also I didn't have any great success. But then it was kind of a longer-term thing. These other things I just dipped into and I wanted to do something, so I did some analyses. This I was approaching on a kind of a longer-term basis.
+
<p>'''Townes:''' </p>
  
=== U.S. decisions about involvement in World War II  ===
+
<p>That's right. So that was a start. </p>
  
'''Nebeker: '''
+
=== Interaction between engineering and physics research at Bell Labs  ===
  
Do you recall the political-military situation in this period? There was something of a stand-off with Hitler unable to invade England. Of course this is before the invasion of Russia in June of '41. But I think throughout this period the United States was becoming more and more involved with Lend-Lease. Do you recall this period?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p><flashmp3>143_-_townes_-_clip_10.mp3</flashmp3></p>
  
Yes, I do in general. There was a lot of discussion about what was going to happen and should we do this or should we do that? And what Roosevelt was doing. Roosevelt obviously was trying very hard to help the British, and one could argue that he was trying to find ways in which we could get involved gracefully because he felt we had to be involved. But a number of people opposed that.  
+
<p>Now one other thing I would have to say about Bell Labs: I think it had a very good atmosphere in not differentiating between physics and engineering in any strong clear-cut way. They had a physics department, and they had various kinds of engineering departments. They had a chemistry department. But there was a lot of interaction. Engineers would work in the physics department a bit, and vice versa. There was a good deal transferred back and forth, and a good deal of interplay. There was not a sharp distinction between the two. I think that was a very good atmosphere from that point. Lovell, for example, was an acoustics physicist. Then he started doing this, and Bell Labs then assigned various engineers to help him out. They made a practice of hiring physicists and then transferring them into engineering. During that period engineering schools did not teach a lot of fundamental physics. Cal Tech was one of the few, and Cal Tech did it simply because it didn't have much of an engineering faculty. [Laughter] I think that's the reason they did it. I was a student there, and the engineering students would take a lot of fundamental physics because they had a small engineering faculty, so the engineers at Cal Tech learned a lot of fundamental physics. </p>
  
'''<br>Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
What was your feeling at the time?
+
<p>Well, also the 'thirties, exactly the period you were at Cal Tech, was a period of real change in EE curricula across the country. Until the 'thirties it was fairly rare even for the electrical engineers to get [[Maxwell's Equations|Maxwell's theory]] in any comprehensive way. But then in the 'thirties at MIT and Cornell and other places, a lot of physics came into the EE curriculum. So one can certainly understand why if in the 'thirties Bell Labs wanted sophisticated fundamental engineering, they would go to the physicists. </p>
  
<br>'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I felt it was likely, but still kind of unthinkable. Kind of unthinkable that we should be in the war.  
+
<p>Yes. Right. They'd convert the physicists. They'd bring them in, and they'd put them in an engineering department normally. I was a rare exception. I never figured out why I was so privileged, but generally they would just put them in a department wherever they wanted them. I knew a lot of my friends who went on into engineering and management picked it up at Bell Labs. The old-time engineers weren't very much trained in fundamental physics. Fundamental physics was coming in more and more. Now they get a lot of it, of course. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>Right. </p>
  
Did you think the United States should do all it could to stay out of the war?
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>There was a strong interaction within Bell Labs, and lots were transferred back and forth. There was just no sharp division. </p>
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
I thought we ought to do as much as we could reasonably to help but not overtly enter the war unless something else happened. That was my feeling. If England had been attacked at that point in a way which was completely threatening to it, I don't know what I would have said. It probably would have been too late for us to get going even. [Chuckling] I was not exactly opposed to doing something overt. On the other hand, I was not highly in favor of it either. I didn't see a way for us to get involved in any very clean way. Even though we might help them in minor ways, we might help out in some particular attack or something, but how could we reasonably get involved? In a sense it was very lucky that the Japanese attacked the way they did, and that swung the whole nation around. Because I think a lot of people were troubled by the same thing: Why should we get involved in Europe's troubles again? Is there a real reason? Well, yes, there's a kind of a reason, but there's no occasion. What could you back it up with?<br>  
+
<p>So when you were working on some of these problems with electron tubes, there were people around you could ask if you had some question in electronics engineering? </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Well, it could have been the same sort of thing as happened in World War I. That is, more German U-boat attacks with escalating tension.<br>  
+
<p>Oh, yes. There were engineers who'd been making tubes in a practical way for the system. There were also some physicists mixed with them. So it was a fairly effective kind of mixture. </p>
  
=== Secret research on computers' use for anti-aircraft guns ===
+
=== Radar bombing system research  ===
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
There might have been, and people were thinking of that, and those kinds of things were happening. The Germans were being pretty aggressive, and those kinds of things were happening, and they were talking about what could get us in again. But mostly I think everybody wanted to help but just didn't feel there was a good reason for actually jumping in. There was, again, an increasing interest in the technology. I think by then Lovell's group must have started, and that was highly secret.<br>  
+
<p>I've read about how you were quite suddenly told--it must have been in March of '41--you were going to be working on the radar bombing system. You started a new notebook; the first entry is dated the third of March. You start work on Case 37616, which again wasn't in the database. From what we can see here on these pages, it's a servomechanism probably for a radar system. What do you recall? This is the next notebook.'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Well, what I remember is I guess [[Harvey Fletcher|Harvey Fletcher]], Wooldridge, one other, and myself were playing the lead. We were to report to Kelly. He had a new assignment [for us]. Although Wooldridge may have been tipped off a bit about it, I had known nothing about it at all. So I think maybe Kelly came into the office at that point, and he said, "Well, this is your new assignment. The war is unfortunately likely to hit us, is approaching, and we've got to help out. I want you to start working on a system for bombing by radar, using the new techniques which Lovell had been working on for anti-aircraft guns." Lovell and other people felt that this could be useful and workable. We would design a system using radar which would then allow bombardiers to use this system rather than the classical Norden bombsight. </p>
  
Whose group?
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Was this all of Wooldridge's group that was suddenly reassigned? </p>
  
Lovell's. He had the idea of doing anti-aircraft aiming using analog computers, electronic computers. The whole thing started by his somehow getting interested in--and maybe he'd done something on this before--using potentiometers for computing. Basically you rotate a potentiometer at a given place, and you get a given voltage, and so you vary voltages around in an electromechanical computing system. It's completely analog. <br>  
+
<p>'''Townes: ''' </p>
  
 +
<p>No, I'm not sure how big a group he had at that point. It wasn't a very big group. I can't remember if there was anybody else directly from that group. But there might have been.'''Nebeker:''' </p>
  
 +
<p>Who did you report to then in the beginning in this? </p>
  
That led him to suggest using this for anti-aircraft guns. Anti-aircraft, that was a very hot topic at that time because the Germans were bombing Great Britain. So he was immediately gotten started on that. So he felt he had an idea and wanted to do it. It was a new idea. Everything else was mechanical and optical, and here he's going to put in some electronics and some electronic computing, as primitive as it was, and it seemed like an advance. So he made this anti-aircraft system, and it worked. Now I didn't know a lot about it.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''  
+
<p>I reported to Wooldridge. Now whom did Wooldridge report to? I'm not sure whom Wooldridge reported to in the beginning. Later he reported to Walter McNair. But I think that was a little later in the war. At that point he may possibly have continued to report to Fletcher. I don't remember. Anyhow, we were called in, and next Monday we were starting our work. [Chuckling] Well, that was pretty sudden and unexpected, and I wasn't accustomed to being treated that way. I talked with Wooldridge. He obviously had been tipped off a bit about it, but it had been somewhat sudden to him, too. We then tried to learn what Lovell was doing and how he was doing it. We were also assigned some engineers to help us out. For example, I knew very little about amplifiers at that time. I don't think Wooldridge knew anything about them either. There was a good practical engineer who said, "Well, you can consult me whenever questions like this come up." Part of the time at least he sat in the same room with me, and he would help us out. He was really working for Lovell, as I remember, but he would be available anytime we needed him. Then they assigned a mechanic. At one point Sid Darlington worked with us. I don't remember whether he came in at the very beginning. I kind of think he did. [[Sidney Darlington|Sid Darlington]] was a mathematician, an applied mathematician. Again, the mathematics department was very accustomed to doing engineering-type analysis. They worked a lot on noise and acoustics and things of this type. Sid Darlington was youngish then and a very capable mathematician. So he would help us out. Now our goal was to try to build something within one year's time, and you could never do that these days. But we were supposed to build something, and obviously everything was rush. </p>
  
Where was that work being done?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>How many people were in your group? </p>
  
That was at Bell Labs.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>I think there were about six, including technicians. I remember a technician, an engineer, and a machinist. And I think Sid Darlington, myself, Wooldridge. There may have been one or two more people, but that was it. So we just first sat down to design a system. Wooldridge was very good at it, and he was a very bright person. We all worked together. Sid Darlington--I think he was with us that early-- Joe Burton was another person who worked with us later; he was a physicist converted into this. I think he came along somewhat later.So we sat down to try to learn the business and design a system and begin construction. It was based on the technology that Lovell had worked out, which was relatively simple. He explained the main ideas of electromechanical computation, and you had to decide what equations you wanted to solve and what to do and how to solve them. The radar part of it, though, was not specifically ours. That would be done out at Whippany where there was a radar group. We were to collaborate with the people at Whippany, who were developing the radar. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
West Street?  
+
<p>You were still at West Street? </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>We were at West Street. They were developing the radar and already had things underway. They were making radars for radar purposes. Whippany was a big center then for the radar systems. Newhouse was the person, an engineer, in charge of that. Frank Goss was an engineer under him who worked on this. So the group, if you include the radar group, was larger. There were probably another half a dozen people there. They were already somewhat along in developing radar, not specifically for this but doing things that were easily applicable to this. What we had to do was to design an overall system. Newhouse did not report to Wooldridge nor vice versa. It was a parallel team, but we worked closely together. So we went out to Whippany to try to learn things out there, see just what the radar would do and what it wouldn't do, and then design a system. We built it, and we put it together. We had technicians to help us out in building circuits. [Chuckling] It was my first real experience with amplifiers, so I learned a lot. Learned a good deal about electronics and systems. The first system we built I'm not clear just when we got it ready--but we set it in a plane and got it ready sometime during the winter or spring. I remember it was cold, and we were flying out of Tampa, Florida. </p>
  
Bell Labs, West Street. I realized that was going on, I knew some of the people who were doing it, and so I knew sort of in general what they were doing. But it was secret, and I didn't have much to do with it. The computing business, of course, was very different then. George Stibitz was a mathematician; you may know about him. I remember very well his rolling around a relay rack. This was after I was over in New Jersey at Bell Labs; it was during the war. He was rolling around a relay rack to show people how you could compute with relays. He said, "Look, you've got to do it digitally. Otherwise you'll never get any precision. You have to do it digitally." Well, he was doing it with relays. [Chuckling] A rack full of mechanical things. [Laughter] <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Could that have already been the winter of '41-'42? That would be less than a year after you started. </p>
  
Doing simple addition.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''  
+
<p>Well, yes. It was the winter of '41-'42, or the spring of '42. I was married by then. I'd gotten married in the spring of '41. Since all this was secret, I wasn't supposed to talk to my wife or anybody about it, and some people were fairly careful about secrecy then. But she went down to Florida with me, as did Wooldridge's wife, and we spent some time there on the beach. I remember it being cold and rainy. [Chuckling] I'm sure it was winter. At this point I couldn't pick out the exact date. </p>
  
People were not highly impressed with that. [Laughter] They weren't highly impressed, but, in principle you certainly can get more accuracy. We were doing a similar thing with analog computers, basically potentiometers. Lovell had the idea of shaping a potentiometer so that for a given angle you could get a more arbitrary function. You wound the potentiometer on a card of varying height so that the resistance varied, not linearly but with some other kind of functional form. <br>  
+
<p><flashmp3>143_-_townes_-_clip_11.mp3</flashmp3></p>
  
<br> '''Nebeker: '''  
+
<p>We did our first bombing exercise, bombing a ship that was anchored offshore. One of the curious things is that the Norden bombsight was so highly thought of at that time--and that made it so secret--that even though we were supposed to be designing a bombing system they would not tell us anything about the Norden bombsight. We couldn't see it, we couldn't know what it did. We asked our Air Force representatives "What kind of precision do you get? What kind of precision do you need?" They would just say, "Just do the best you can." People talk about the Norden bombsight dropping bombs in pickle barrels, and they had great stories about it. But the actual accuracy was not all that good, and particularly in Europe where the poor bombardiers had to make a long straight run in order to drop the bomb. We knew that that was a danger, and part of our effort was to try to see that one could maneuver and compute at the same time. In order to get the position of the plane relative to the target, you had to know the height and the wind speed, and of course the ballistics of the missile, and the direction of the plane, and its velocity. So basically you needed to calculate the wind speed and the drift from observing the ground. We argued right from the beginning we should be able to maneuver and do that. As long as you kept track of the plane's speed and orientation, that you could calculate the wind speed without that, and it would not make the poor bombardier run a straight course. So part of the idea was to do that, give him more flexibility, and part of it was to be able to bomb at night and through clouds when he couldn't see anything. </p>
  
Right. So it's something like a function generator?
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Right. </p>
  
'''Townes:'''  
+
<p>'''Townes: ''' </p>
  
That's right. So that was a start.<br>
+
<p>The very first run we had, we had a colonel who was a very nice person; we had a lot of different pilots during that period. Four of them in particular during the war, and three of them were killed in accidents. Fortunately, we never had an accident. But three out of four of our pilots were killed in accidents, and they were generally test-pilot types. This colonel flew us, and the first bomb we dropped we had a run at an altitude of 5,000 feet. 5,000 feet was a reasonably high altitude at that point. We dropped the bomb, and I quickly dashed up to the cabin to see what happened. It missed by about a hundred feet. And this colonel, who wouldn't tell us anything about the Norden bombsight--yes, sure, he'd used it. He couldn't say a thing about it. So then he said, "That's a damned good shot, if you ask me." [Chuckling] That boosted our morale a great deal, and gave us our first real information on the accuracy then. </p>
  
=== Interaction between engineering and physics research at Bell Labs  ===
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Why was it necessary for you to accompany the equipment on the test flights? </p>
  
Now one other thing I would have to say about Bell Labs: I think it had a very good atmosphere in not differentiating between physics and engineering in any strong clear-cut way. They had a physics department, and they had various kinds of engineering departments. They had a chemistry department. But there was a lot of interaction. Engineers would work in the physics department a bit, and vice versa. There was a good deal transferred back and forth, and a good deal of interplay. There was not a sharp distinction between the two. I think that was a very good atmosphere from that point. Lovell, for example, was an acoustics physicist. Then he started doing this, and Bell Labs then assigned various engineers to help him out. They made a practice of hiring physicists and then transferring them into engineering. During that period engineering schools did not teach a lot of fundamental physics. Cal Tech was one of the few, and Cal Tech did it simply because it didn't have much of an engineering faculty. [Laughter] I think that's the reason they did it. I was a student there, and the engineering students would take a lot of fundamental physics because they had a small engineering faculty, so the engineers at Cal Tech learned a lot of fundamental physics.
+
<p>'''Townes:''' </p>
  
<br>  
+
<p>This was a prototype system, and absolutely nobody else knew how to run it. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Well, also the 'thirties, exactly the period you were at Cal Tech, was a period of real change in EE curricula across the country. Until the 'thirties it was fairly rare even for the electrical engineers to get Maxwell's theory in any comprehensive way. But then in the 'thirties at MIT and Cornell and other places, a lot of physics came into the EE curriculum. So one can certainly understand why if in the 'thirties Bell Labs wanted sophisticated fundamental engineering, they would go to the physicists.
+
<p>You couldn't train some bombardier to use this prototype? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes. Right. They'd convert the physicists. They'd bring them in, and they'd put them in an engineering department normally. I was a rare exception. I never figured out why I was so privileged, but generally they would just put them in a department wherever they wanted them. I knew a lot of my friends who went on into engineering and management picked it up at Bell Labs. The old-time engineers weren't very much trained in fundamental physics. Fundamental physics was coming in more and more. Now they get a lot of it, of course.  
+
<p>We probably could have, but in any prototype system, there are always going to be problems. Something always breaks down. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Right.<br>  
+
<p>Somebody would have to be there. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
There was a strong interaction within Bell Labs, and lots were transferred back and forth. There was just no sharp division. <br>  
+
<p>You'd really have to know the system. So in checking it out the engineers who'd designed the system really had to be there. This was not a production unit. We never made production units. Our job was to make a prototype system, and demonstrate it, and check it out, and see that it worked. Then it could be duplicated. Then somebody could be trying to use it. We could have trained somebody to do it, but we had to be there anyhow, and it was much more effective for us to operate it and see just exactly how it was going. So Wooldridge and I were sitting back watching the radar signals and guiding the plane. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
So when you were working on some of these problems with electron tubes, there were people around you could ask if you had some question in electronics engineering?  
+
<p>Were one of you acting as bombardier? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Oh, yes. There were engineers who'd been making tubes in a practical way for the system. There were also some physicists mixed with them. So it was a fairly effective kind of mixture.<br>  
+
<p>Yes, except we had an automatic release. Basically we were watching the radar tuning the equipment, and the instruments, and watching everything. The needle showed the pilot how to turn. The pilot had a needle, which allowed the pilot to move it back and forth as much as he wanted, and then at a certain time he had to turn on course. Put that needle exactly in the middle. That was his job, and then it automatically released when the computer told it to release. </p>
  
=== Radar bombing system research  ===
+
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>Yes. I see. </p>
  
I've read about how you were quite suddenly told--it must have been in March of '41--you were going to be working on the radar bombing system. You started a new notebook; the first entry is dated the third of March. You start work on Case 37616, which again wasn't in the database. From what we can see here on these pages, it's a servomechanism probably for a radar system. What do you recall? This is the next notebook.<br> <br> '''Townes: '''  
+
<p>'''Townes:''' </p>
  
Well, what I remember is I guess Harvey Fletcher, Wooldridge, one other, and myself were playing the lead. We were to report to Kelly. He had a new assignment [for us]. Although Wooldridge may have been tipped off a bit about it, I had known nothing about it at all. So I think maybe Kelly came into the office at that point, and he said, "Well, this is your new assignment. The war is unfortunately likely to hit us, is approaching, and we've got to help out. I want you to start working on a system for bombing by radar, using the new techniques which Lovell had been working on for anti-aircraft guns." Lovell and other people felt that this could be useful and workable. We would design a system using radar which would then allow bombardiers to use this system rather than the classical Norden bombsight. <br>  
+
<p>We were watching the instruments primarily and the radar signals. We tracked on radar. That was another thing. You had to track on the radar signals. There was not an automatic tracking. You had to track on the radar signals. That's how it worked. This is where I learned about servosystems. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Was this all of Wooldridge's group that was suddenly reassigned? <br>  
+
<p>This is the very first page on that project. On the second page we can already see some of the mathematics involved. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
No, I'm not sure how big a group he had at that point. It wasn't a very big group. I can't remember if there was anybody else directly from that group. But there might have been.<br> <br> '''Nebeker:'''
+
<p>Yes. That's right. Some of the mathematics for the equations which the system solved. </p>
  
Who did you report to then in the beginning in this? <br>  
+
<p>'''Nebeker:''' </p>
  
<br> '''Townes: '''
+
<p>So you're learning at this time a lot about systems and electronics and also this quite new field of analog computation. </p>
  
I reported to Wooldridge. Now whom did Wooldridge report to? I'm not sure whom Wooldridge reported to in the beginning. Later he reported to Walter McNair. But I think that was a little later in the war. At that point he may possibly have continued to report to Fletcher. I don't remember. Anyhow, we were called in, and next Monday we were starting our work. [Chuckling] Well, that was pretty sudden and unexpected, and I wasn't accustomed to being treated that way. I talked with Wooldridge. He obviously had been tipped off a bit about it, but it had been somewhat sudden to him, too. We then tried to learn what Lovell was doing and how he was doing it. We were also assigned some engineers to help us out. For example, I knew very little about amplifiers at that time. I don't think Wooldridge knew anything about them either. There was a good practical engineer who said, "Well, you can consult me whenever questions like this come up." Part of the time at least he sat in the same room with me, and he would help us out. He was really working for Lovell, as I remember, but he would be available anytime we needed him. Then they assigned a mechanic. At one point Sid Darlington worked with us. I don't remember whether he came in at the very beginning. I kind of think he did. Sid Darlington was a mathematician, an applied mathematician. Again, the mathematics department was very accustomed to doing engineering-type analysis. They worked a lot on noise and acoustics and things of this type. Sid Darlington was youngish then and a very capable mathematician. So he would help us out. Now our goal was to try to build something within one year's time, and you could never do that these days. But we were supposed to build something, and obviously everything was rush. <br> <br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
How many people were in your group?<br> <br> '''Townes: '''
+
<p>Also stability of feedback circuits. Hendrik Bode was at Bell Labs at that time, and he was a member of the mathematics department. I had to think about and learn Bode's theories and get well acquainted with built-in feedback systems. Well, yeah, this is a set of equations. </p>
  
I think there were about six, including technicians. I remember a technician, an engineer, and a machinist. And I think Sid Darlington, myself, Wooldridge. There may have been one or two more people, but that was it. So we just first sat down to design a system. Wooldridge was very good at it, and he was a very bright person. We all worked together. Sid Darlington--I think he was with us that early-- Joe Burton was another person who worked with us later; he was a physicist converted into this. I think he came along somewhat later.<br> <br> So we sat down to try to learn the business and design a system and begin construction. It was based on the technology that Lovell had worked out, which was relatively simple. He explained the main ideas of electromechanical computation, and you had to decide what equations you wanted to solve and what to do and how to solve them. The radar part of it, though, was not specifically ours. That would be done out at Whippany where there was a radar group. We were to collaborate with the people at Whippany, who were developing the radar. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>On page 6 there's a heading: "Maximum Velocity Necessary for Motors"? </p>
  
You were still at West Street? <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>These are the motors that drive the potentiometers, I guess. Let me see. </p>
  
We were at West Street. They were developing the radar and already had things underway. They were making radars for radar purposes. Whippany was a big center then for the radar systems. Newhouse was the person, an engineer, in charge of that. Frank Goss was an engineer under him who worked on this. So the group, if you include the radar group, was larger. There were probably another half a dozen people there. They were already somewhat along in developing radar, not specifically for this but doing things that were easily applicable to this. What we had to do was to design an overall system. Newhouse did not report to Wooldridge nor vice versa. It was a parallel team, but we worked closely together. So we went out to Whippany to try to learn things out there, see just what the radar would do and what it wouldn't do, and then design a system. We built it, and we put it together. We had technicians to help us out in building circuits. [Chuckling] It was my first real experience with amplifiers, so I learned a lot. Learned a good deal about electronics and systems. The first system we built I'm not clear just when we got it ready--but we set it in a plane and got it ready sometime during the winter or spring. I remember it was cold, and we were flying out of Tampa, Florida. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>It says, "Potentiometer must move complete circle in about 20 seconds." In the middle of that page. </p>
  
Could that have already been the winter of '41-'42? That would be less than a year after you started.<br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Well, yes. It was the winter of '41-'42, or the spring of '42. I was married by then. I'd gotten married in the spring of '41. Since all this was secret, I wasn't supposed to talk to my wife or anybody about it, and some people were fairly careful about secrecy then. But she went down to Florida with me, as did Wooldridge's wife, and we spent some time there on the beach. I remember it being cold and rainy. [Chuckling] I'm sure it was winter. At this point I couldn't pick out the exact date.  
+
<p>Yes. Right. We had the motor geared down so it was set to calculating the speed and distance. </p>
  
<br> We did our first bombing exercise, bombing a ship that was anchored offshore. One of the curious things is that the Norden bombsight was so highly thought of at that time--and that made it so secret--that even though we were supposed to be designing a bombing system they would not tell us anything about the Norden bombsight. We couldn't see it, we couldn't know what it did. We asked our Air Force representatives "What kind of precision do you get? What kind of precision do you need?" They would just say, "Just do the best you can." People talk about the Norden bombsight dropping bombs in pickle barrels, and they had great stories about it. But the actual accuracy was not all that good, and particularly in Europe where the poor bombardiers had to make a long straight run in order to drop the bomb. We knew that that was a danger, and part of our effort was to try to see that one could maneuver and compute at the same time. In order to get the position of the plane relative to the target, you had to know the height and the wind speed, and of course the ballistics of the missile, and the direction of the plane, and its velocity. So basically you needed to calculate the wind speed and the drift from observing the ground. We argued right from the beginning we should be able to maneuver and do that. As long as you kept track of the plane's speed and orientation, that you could calculate the wind speed without that, and it would not make the poor bombardier run a straight course. So part of the idea was to do that, give him more flexibility, and part of it was to be able to bomb at night and through clouds when he couldn't see anything.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Now this is real system engineering work. </p>
  
Right.
+
<p>'''Townes: ''' </p>
  
<br>'''Townes: '''
+
<p>That's right. It's invention as you go along, too. </p>
  
The very first run we had, we had a colonel who was a very nice person; we had a lot of different pilots during that period. Four of them in particular during the war, and three of them were killed in accidents. Fortunately, we never had an accident. But three out of four of our pilots were killed in accidents, and they were generally test-pilot types. This colonel flew us, and the first bomb we dropped we had a run at an altitude of 5,000 feet. 5,000 feet was a reasonably high altitude at that point. We dropped the bomb, and I quickly dashed up to the cabin to see what happened. It missed by about a hundred feet. And this colonel, who wouldn't tell us anything about the Norden bombsight--yes, sure, he'd used it. He couldn't say a thing about it. So then he said, "That's a damned good shot, if you ask me." [Chuckling] That boosted our morale a great deal, and gave us our first real information on the accuracy then. '''<br>'''
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Sure. </p>
  
Why was it necessary for you to accompany the equipment on the test flights? '''<br>'''  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes:'''
+
<p>But it's system engineering, and it had a function to fulfill. So that's what we were doing. </p>
  
This was a prototype system, and absolutely nobody else knew how to run it.<br> <br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
You couldn't train some bombardier to use this prototype?<br> <br> '''Townes: '''
+
<p>Did you find this interesting to find ways for this kind of function? </p>
  
We probably could have, but in any prototype system, there are always going to be problems. Something always breaks down.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Well, yes. It was interesting. It was new to me, and so interesting. Sure. I felt in itself it was interesting. I was pleased to learn about it even though this wasn't what I wanted to do in the long run. I was engaged with the analysis of it. I adapted to it, I guess, reasonably well. I didn't find it uninteresting. </p>
  
Somebody would have to be there. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>There is also some mechanical engineering, for example, on page 29 the calculation of the torque of the motors. </p>
  
You'd really have to know the system. So in checking it out the engineers who'd designed the system really had to be there. This was not a production unit. We never made production units. Our job was to make a prototype system, and demonstrate it, and check it out, and see that it worked. Then it could be duplicated. Then somebody could be trying to use it. We could have trained somebody to do it, but we had to be there anyhow, and it was much more effective for us to operate it and see just exactly how it was going. So Wooldridge and I were sitting back watching the radar signals and guiding the plane. '''<br>'''
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Oh, yes. Right. </p>
  
Were one of you acting as bombardier?
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>On page 31, just two pages further. You've got a condition for non-binding of worm gears that you've got to check. I'm sure your Cal Tech training in mechanics proved useful in all of this. [Laughter] </p>
  
Yes, except we had an automatic release. Basically we were watching the radar tuning the equipment, and the instruments, and watching everything. The needle showed the pilot how to turn. The pilot had a needle, which allowed the pilot to move it back and forth as much as he wanted, and then at a certain time he had to turn on course. Put that needle exactly in the middle. That was his job, and then it automatically released when the computer told it to release. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I'd taken a mechanics course but no engineering. But these are things which are fun to work out. And I was forced to think about them. </p>
  
Yes. I see.<br> <br>'''Townes:'''  
+
<p>'''Nebeker: ''' </p>
  
We were watching the instruments primarily and the radar signals. We tracked on radar. That was another thing. You had to track on the radar signals. There was not an automatic tracking. You had to track on the radar signals. That's how it worked. This is where I learned about servosystems.<br> <br> '''Nebeker: '''
+
<p>Page 33, exhibit possible slowing of the worm gear. </p>
  
This is the very first page on that project. On the second page we can already see some of the mathematics involved. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes. Various torques. Boy, I don't remember all of this. </p>
  
Yes. That's right. Some of the mathematics for the equations which the system solved.<br>Nebeker: So you're learning at this time a lot about systems and electronics and also this quite new field of analog computation. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>That seems fairly sophisticated mechanical engineering if you look at page 33 there. That tooth of the gear and the forces that are involved there. </p>
  
Also stability of feedback circuits. Hendrik Bode was at Bell Labs at that time, and he was a member of the mathematics department. I had to think about and learn Bode's theories and get well acquainted with built-in feedback systems. Well, yeah, this is a set of equations.<br> <br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
On page 6 there's a heading: "Maximum Velocity Necessary for Motors"?<br> <br> '''Townes: '''
+
<p>Well, you know, it illustrates that principles apply really very broadly, scientific principles. [Chuckling] Or engineering principles. Apply very broadly across a lot of different fields. If you know something very thoroughly, you can make some headway in a lot of different areas. I had had fundamental physics and mechanics and electricity and magnetism. </p>
  
These are the motors that drive the potentiometers, I guess. Let me see. <br> <br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
It says, "Potentiometer must move complete circle in about 20 seconds." In the middle of that page.<br> <br> '''Townes: '''
+
<p>What can you tell me about page 40? </p>
  
Yes. Right. We had the motor geared down so it was set to calculating the speed and distance.<br> <br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Now this is real system engineering work. <br>  
+
<p>Oh, yes. Here's another one of those schematics. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
That's right. It's invention as you go along, too.<br> <br>  
+
<p>Its head is: "Consideration of Current Drawn by Various Potentiometers and Accuracy Necessary and Corrections." These are the calculating potentiometers? </p>
  
'''Nebeker: '''  
+
<p>'''Townes:''' </p>
  
Sure. <br>  
+
<p>Yes, these were the calculating potentiometers, and there's the necessary fractional accuracy. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
But it's system engineering, and it had a function to fulfill. So that's what we were doing.<br> <br>  
+
<p>Was your group actually building these potentiometers? </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Did you find this interesting to find ways for this kind of function? <br>  
+
<p>Yes, we wound them. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Well, yes. It was interesting. It was new to me, and so interesting. Sure. I felt in itself it was interesting. I was pleased to learn about it even though this wasn't what I wanted to do in the long run. I was engaged with the analysis of it. I adapted to it, I guess, reasonably well. I didn't find it uninteresting. <br> <br> '''Nebeker: '''
+
<p>And then you'd help in the testing of them? </p>
  
There is also some mechanical engineering, for example, on page 29 the calculation of the torque of the motors.<br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Oh, yes. Right.<br> <br> '''Nebeker: '''
+
<p>Yes, yes. I think the Lovell group was already doing some of this. We just learned from them. I don't remember interacting with the Lovell group very strongly after the first few weeks on this kind of thing. But they were always there, and they'd been in the game for, oh, probably a year and a half or two before we started. They had already made a successful system. </p>
  
On page 31, just two pages further. You've got a condition for non-binding of worm gears that you've got to check. I'm sure your Cal Tech training in mechanics proved useful in all of this. [Laughter] <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I'm trying to understand how this analog computer worked. Looking again at page 40, are you developing a set of calculating elements with these different potentiometers which you would then use as necessary for the particular calculation? </p>
  
I'd taken a mechanics course but no engineering. But these are things which are fun to work out. And I was forced to think about them. <br> <br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Page 33, exhibit possible slowing of the worm gear.<br> <br> '''Townes: '''
+
<p>Yes. Right. If you look at the next page, it says, "Computing Circuit." SD. That's Sid Darlington. So he was with us from the beginning. </p>
  
Yes. Various torques. Boy, I don't remember all of this.<br> <br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
That seems fairly sophisticated mechanical engineering if you look at page 33 there. That tooth of the gear and the forces that are involved there. <br>  
+
<p>That's right, because that's March of '41. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Well, you know, it illustrates that principles apply really very broadly, scientific principles. [Chuckling] Or engineering principles. Apply very broadly across a lot of different fields. If you know something very thoroughly, you can make some headway in a lot of different areas. I had had fundamental physics and mechanics and electricity and magnetism.<br> <br> '''Nebeker: '''
+
<p>Yes. Sid Darlington. Now Sid was very familiar with electronic circuits. He'd been very close to [[Hendrik W. Bode|Hendrik Bode]] and the people in the mathematics department. But again, they were really doing engineering. It was a mathematical kind of engineering, and Bode's Theorem, came out of that. Sid Darlington was very familiar with those, which I wasn't initially. So he was helpful there. He evidently drew this circuit or had it drawn up; probably he did it himself after we had laid it out and talked about it. Basically you end up with a steering circuit. </p>
  
What can you tell me about page 40?<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Oh, yes. Here's another one of those schematics. <br> <br> '''Nebeker: '''
+
<p>What is being steered? </p>
  
Its head is: "Consideration of Current Drawn by Various Potentiometers and Accuracy Necessary and Corrections." These are the calculating potentiometers?<br> <br> '''Townes:'''  
+
<p>'''Townes: ''' </p>
  
Yes, these were the calculating potentiometers, and there's the necessary fractional accuracy. <br> <br> '''Nebeker: '''
+
<p>What is being steered is the airplane. </p>
  
Was your group actually building these potentiometers?<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes, we wound them. <br>  
+
<p>Okay. </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Nebeker: '''
+
<p>This is the needle. You end up with a needle that tells the plane where or how to turn. Particularly just before the drop, where to turn. That depends on the crosswinds and various sorts of things where the plane is and the ballistics of the bomb. There is also a release circuit. </p>
  
And then you'd help in the testing of them?<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes, yes. I think the Lovell group was already doing some of this. We just learned from them. I don't remember interacting with the Lovell group very strongly after the first few weeks on this kind of thing. But they were always there, and they'd been in the game for, oh, probably a year and a half or two before we started. They had already made a successful system. <br>  
+
<p>I see. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I'm trying to understand how this analog computer worked. Looking again at page 40, are you developing a set of calculating elements with these different potentiometers which you would then use as necessary for the particular calculation?<br> <br> '''Townes: '''
+
<p>When these things come together and go through zero, that releases the bomb. You put in voltages representing the different variables, and you come out with a voltage that tells you how to turn the plane, and a voltage that tells you when to release the bomb. That's a computing system. </p>
  
Yes. Right. If you look at the next page, it says, "Computing Circuit." SD. That's Sid Darlington. So he was with us from the beginning. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>These input voltages. Where are they coming from? </p>
  
That's right, because that's March of '41. <br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes. Sid Darlington. Now Sid was very familiar with electronic circuits. He'd been very close to Hendrik Bode and the people in the mathematics department. But again, they were really doing engineering. It was a mathematical kind of engineering, and Bode's Theorem, came out of that. Sid Darlington was very familiar with those, which I wasn't initially. So he was helpful there. He evidently drew this circuit or had it drawn up; probably he did it himself after we had laid it out and talked about it. Basically you end up with a steering circuit. <br>  
+
<p>We had an altimeter, which is basically a pressure measurement, in the plane. We had a air velocity measuring device. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
What is being steered?<br> <br> '''Townes: '''
+
<p>I don't know the instrumentation technology at that time. Could you get a voltage out of an altimeter immediately, or did you have to work that out, too? </p>
  
What is being steered is the airplane. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>At that time we set it by hand, the altitude. The plane kept a constant altitude. </p>
  
Okay.<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
This is the needle. You end up with a needle that tells the plane where or how to turn. Particularly just before the drop, where to turn. That depends on the crosswinds and various sorts of things where the plane is and the ballistics of the bomb. There is also a release circuit. <br>  
+
<p>I see. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I see.<br> <br> '''Townes: '''
+
<p>You kept a constant altitude, and you set that by hand. Initially I think the velocity was constant. Then later we mechanized it so we'd have a varying velocity. I think initially the velocity was constant. So you would read that and set it in by hand. </p>
  
When these things come together and go through zero, that releases the bomb. You put in voltages representing the different variables, and you come out with a voltage that tells you how to turn the plane, and a voltage that tells you when to release the bomb. That's a computing system.<br> <br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
These input voltages. Where are they coming from? <br> <br> '''Townes: '''
+
<p>Okay. Just turning a dial. </p>
  
We had an altimeter, which is basically a pressure measurement, in the plane. We had a air velocity measuring device. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes, yes. The plane kept the constant altitude, and constant air velocity, but could turn. Then you'd put in the various constants of the bomb by hand. You'd track the radar signal electrically anyhow on a scope, you'd put cross hairs on the scope. </p>
  
I don't know the instrumentation technology at that time. Could you get a voltage out of an altimeter immediately, or did you have to work that out, too?<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
At that time we set it by hand, the altitude. The plane kept a constant altitude. <br> <br> '''Nebeker: '''
+
<p>The bombardier, that's his job? </p>
  
I see.<br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
You kept a constant altitude, and you set that by hand. Initially I think the velocity was constant. Then later we mechanized it so we'd have a varying velocity. I think initially the velocity was constant. So you would read that and set it in by hand.<br> <br> '''Nebeker: '''
+
<p>He tracks the target, and to track a target, you turn things, and that puts in voltages. By tracking a target, that gives you then the information from which you can calculate the wind speed and direction and all of that. </p>
  
Okay. Just turning a dial.<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes, yes. The plane kept the constant altitude, and constant air velocity, but could turn. Then you'd put in the various constants of the bomb by hand. You'd track the radar signal electrically anyhow on a scope, you'd put cross hairs on the scope.<br> <br> '''Nebeker: '''
+
<p>I see. </p>
  
The bombardier, that's his job?<br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
He tracks the target, and to track a target, you turn things, and that puts in voltages. By tracking a target, that gives you then the information from which you can calculate the wind speed and direction and all of that.<br> <br> '''Nebeker: '''
+
<p>This is the initial system here. </p>
  
I see.<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
This is the initial system here.<br> <br> '''Nebeker: '''
+
<p>That was arrived at very quickly. </p>
  
That was arrived at very quickly. <br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes.<br> <br> '''Nebeker: '''
+
<p>Yes. </p>
  
Was the group going before you joined?<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
No.<br> <br> '''Nebeker: '''
+
<p>Was the group going before you joined? </p>
  
So in the space of a month you had this whole thing worked out.<br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
In one sense this is a simple system by comparison with what people do these days. It was new then, but nevertheless a simple system by comparison to what we do now. As the war went on, we put in more and more complications. We put in systems for both optical and radar guiding, for example. The last systems were built for all of those characteristics. We put in more complications as time went on, perfections and so on. But this was the first system, and that's the one we tried out first down in Florida. We moved fast. It was a small group and a good group of people. We just had to decide things, and so we did.  
+
<p>No. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
On the next page, there's a servo for rotating the antenna about a horizontal axis. Is this for automatic tracking?<br> <br> '''Townes: '''
+
<p>So in the space of a month you had this whole thing worked out. </p>
  
Yes, this was to keep the antenna on the target as the plane rotated and turned. As the plane advanced. The target was not always directly in front of it. I think the antenna probably had a potentiometer on it, too. I've forgotten details. The axes for three degrees of freedom were not terribly accurate. The beam width is moderately wide. Then we had relays for controlling some of the power. Mechanical relays always give us trouble. [Chuckling] Mechanical relays and vacuum tubes, and those were the best that were available at the time. And by the end of the war I felt we had as many as we could afford. Otherwise, the troubles with them would be too frequent. <br>  
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>In one sense this is a simple system by comparison with what people do these days. It was new then, but nevertheless a simple system by comparison to what we do now. As the war went on, we put in more and more complications. We put in systems for both optical and radar guiding, for example. The last systems were built for all of those characteristics. We put in more complications as time went on, perfections and so on. But this was the first system, and that's the one we tried out first down in Florida. We moved fast. It was a small group and a good group of people. We just had to decide things, and so we did. </p>
  
The system was about as complex as you could afford to build at that time, with the tubes frequently going out. We had to have very controlled qualities for the tubes. The tubes had to be linear and accurate; this was a d.c. computation. So the d.c. drifts from the tubes had to be small. We even had a special tube with a special number made with those specifications.<br> <br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
That could be done with a tube group at Bell Labs? <br>  
+
<p>On the next page, there's a servo for rotating the antenna about a horizontal axis. Is this for automatic tracking? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I've forgotten who was making those tubes at that time. I think RCA perhaps. But whoever was making those tubes, it was not Bell Labs.  
+
<p>Yes, this was to keep the antenna on the target as the plane rotated and turned. As the plane advanced. The target was not always directly in front of it. I think the antenna probably had a potentiometer on it, too. I've forgotten details. The axes for three degrees of freedom were not terribly accurate. The beam width is moderately wide. Then we had relays for controlling some of the power. Mechanical relays always give us trouble. [Chuckling] Mechanical relays and vacuum tubes, and those were the best that were available at the time. And by the end of the war I felt we had as many as we could afford. Otherwise, the troubles with them would be too frequent. </p>
  
<br> '''Nebeker: '''
+
<p>The system was about as complex as you could afford to build at that time, with the tubes frequently going out. We had to have very controlled qualities for the tubes. The tubes had to be linear and accurate; this was a d.c. computation. So the d.c. drifts from the tubes had to be small. We even had a special tube with a special number made with those specifications. </p>
  
I see. Some manufacturer. You said, "We need these characteristics."<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Some manufacturer. We simply put on the specifications and asked them if they could give us tubes with that specification. And they said, "Well, yes, okay. That'll be X more expensive, and we'll have to make a special class of tubes." They gave it a separate tube number for that tube. They were then available for other uses, too. But it was much more carefully controlled.<br> <br> '''Nebeker: '''
+
<p>That could be done with a tube group at Bell Labs? </p>
  
That's interesting, that the existing tubes didn't meet that need anyway. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I've forgotten who was making those tubes at that time. I think RCA perhaps. But whoever was making those tubes, it was not Bell Labs. </p>
  
Yes. Well, we were pushing on everything for precision, and that was one of them. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I see. Some manufacturer. You said, "We need these characteristics." </p>
  
This is mid April of '41. There's a system sketched out again. <br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes, I see Sid was the one who sketched that out again. <br> <br> '''Nebeker: '''
+
<p>Some manufacturer. We simply put on the specifications and asked them if they could give us tubes with that specification. And they said, "Well, yes, okay. That'll be X more expensive, and we'll have to make a special class of tubes." They gave it a separate tube number for that tube. They were then available for other uses, too. But it was much more carefully controlled. </p>
  
And on the next page, "Measured by J.H. Kronmeyer". <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>That's interesting, that the existing tubes didn't meet that need anyway. </p>
  
I don't remember who Kronmeyer was. <br> <br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Maybe a technician with your group?<br> <br> '''Townes: '''
+
<p>Yes. Well, we were pushing on everything for precision, and that was one of them. </p>
  
I don't think so. I think we may have gotten somebody else from a different group to make some measurements for us or something. I don't quite remember his name. This is a distance measure, we're checking out a potentiometer.<br> <br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Now this is in the summer of '41. Now let's see. I was looking at page 100. That looks like figuring different ways of calculating something. I guess we can see the dates here on the next page, two pages further on; it's 118. Yeah, this one. "Bombs dropped." <br>  
+
<p>This is mid April of '41. There's a system sketched out again. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Oh, yes.<br> <br>'''Nebeker: '''
+
<p>Yes, I see Sid was the one who sketched that out again. </p>
  
We've got some dates here, February of '42. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>And on the next page, "Measured by J.H. Kronmeyer". </p>
  
Okay. I knew it was in the wintertime. I guess that's when the time was. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I don't remember who Kronmeyer was. </p>
  
Now of course that's a couple of months past Pearl Harbor, and that must have given added urgency to getting the system working. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Maybe a technician with your group? </p>
  
Yes. Now you see altitudes set. We set an altitude. We read the actual altitude. The pilot didn't always stay right on altitude. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I don't think so. I think we may have gotten somebody else from a different group to make some measurements for us or something. I don't quite remember his name. This is a distance measure, we're checking out a potentiometer. </p>
  
I see. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Now this is in the summer of '41. Now let's see. I was looking at page 100. That looks like figuring different ways of calculating something. I guess we can see the dates here on the next page, two pages further on; it's 118. Yeah, this one. "Bombs dropped." </p>
  
We had a set-in altitude for what the actual altitude was. <br> <br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I see. It indicated air speed and true air speed. <br>  
+
<p>Oh, yes.'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>We've got some dates here, February of '42. </p>
  
Yes. One of the standard calculations was for true air speed, and then, from tracking, ground speed. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Okay. I knew it was in the wintertime. I guess that's when the time was. </p>
  
So you had some air speed indicator, and then the system is calculating air speed. Is that right? <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Now of course that's a couple of months past Pearl Harbor, and that must have given added urgency to getting the system working. </p>
  
Well, the air speed indicator depends on air density in part and temperature so you had to correct it. I think this is just standard correction for the way the meter read. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes. Now you see altitudes set. We set an altitude. We read the actual altitude. The pilot didn't always stay right on altitude. </p>
  
Oh, I see. <br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
There was no way of measuring ground speed except by doing the radar tracking, which gave a measurement. I think this here is just the standard correction to the air speed meter.<br> <br> '''Nebeker: '''
+
<p>I see. </p>
  
Okay. And you can see that there's a column, "Range Error." <br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes. <br>  
+
<p>We had a set-in altitude for what the actual altitude was. </p>
  
<br> '''Nebeker:'''  
+
<p>'''Nebeker: ''' </p>
  
And I don't know what that next column heading means.<br> <br> '''Townes: '''
+
<p>I see. It indicated air speed and true air speed. </p>
  
That is the left-right error. Left-right deviation error. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes. One of the standard calculations was for true air speed, and then, from tracking, ground speed. </p>
  
Oh, deviation error maybe. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>So you had some air speed indicator, and then the system is calculating air speed. Is that right? </p>
  
But that's the distance left-right. And you see the very first one. [Chuckling] Hundred-foot range error and zero deviation. The next one wasn't as good. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Well, the air speed indicator depends on air density in part and temperature so you had to correct it. I think this is just standard correction for the way the meter read. </p>
  
But then you had some very good ones.<br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
We would drop a bomb, and then we would come back and take another run and make it from a different direction. <br>  
+
<p>Oh, I see. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Are these averages then? There were six runs on February 12th.<br> <br> '''Townes: '''
+
<p>There was no way of measuring ground speed except by doing the radar tracking, which gave a measurement. I think this here is just the standard correction to the air speed meter. </p>
  
That's right. Six runs on February 12th. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Okay. And you can see that there's a column, "Range Error." </p>
  
February 27th, there are five runs, I guess. And so on. I see. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes. </p>
  
That's right. So those were our bombing runs. <br> <br> '''Nebeker: '''  
+
<p>'''Nebeker:''' </p>
  
It looks impressive, If you look at these range errors down this column. You must have been quite pleased with the system.<br> <br> '''Townes: '''
+
<p>And I don't know what that next column heading means. </p>
  
Well, we didn't know what was supposed to be good. [Chuckling] <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: ''' I would imagine that in a project like this, even to get it working approximately would be a great achievement. <br>  
+
<p>That is the left-right error. Left-right deviation error. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes. Oh, sure. Well, we were thankful it was working. [Chuckling] We'd been working hard. We didn't know what was supposed to be good and what was supposed to be bad. We just did as much as we could in the kind of time available, and got it as accurate as we could with the kind of techniques we had.<br>  
+
<p>Oh, deviation error maybe. </p>
  
 +
<p>'''Townes: ''' </p>
  
 +
<p>But that's the distance left-right. And you see the very first one. [Chuckling] Hundred-foot range error and zero deviation. The next one wasn't as good. </p>
  
Somewhere in here, at some point, I think it was probably later than this, I actually did a statistical analysis of these errors in the system. My impression is that it was one of the very first times that anybody had tried to add up a lot of minor errors in a system to predict the overall performance of a system, just on a probability basis. I made measurements and estimates of all the errors and all the different kinds of parameters and elements. Then added it all up. I remember joking at the time, well, this is what the mathematics says it should be. [Chuckling] Of course nobody knows whether this kind of thing works out or not, but this is what the mathematics says it ought to be. Well, it turned out to work out quite well. That kind of systems analysis is common nowadays. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>But then you had some very good ones. </p>
  
But they weren't then?<br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Nobody that I know else had done then. They all seemed to ignore it. Nor did they want to trust it very far. [Chuckling]<br> <br> '''Nebeker: '''
+
<p>We would drop a bomb, and then we would come back and take another run and make it from a different direction. </p>
  
It sounds like something that Sid Darlington would take to. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Are these averages then? There were six runs on February 12th. </p>
  
Yes. Well, Sid, I think, was ready to believe it.<br> <br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
The idea was that you have these estimates of all these individual errors for the different components of the system. <br>  
+
<p>That's right. Six runs on February 12th. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes. Then you add the sum of squares, assuming Gaussian errors, which you don't know to be Gaussian, but nonetheless it is a first approximation. <br>  
+
<p>February 27th, there are five runs, I guess. And so on. I see. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Then see what error distribution you have for the system as a whole? <br>  
+
<p>That's right. So those were our bombing runs. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
That's right. That was the idea. Get the system error from the component errors. And it's now, very common. Everybody accepts it, everybody does it nowadays, if they're interested. But I think that was one of the first. I don't know of anybody else who was doing it at that time. But that was probably a year or two later than this.  
+
<p>It looks impressive, If you look at these range errors down this column. You must have been quite pleased with the system. </p>
  
==== Torpedo bombing  ====
+
<p>'''Townes: ''' </p>
  
'''Nebeker: '''
+
<p>Well, we didn't know what was supposed to be good. [Chuckling] </p>
  
Or page 130 or another page or two there's a geometry of torpedo bombing. Was that a special version of this computer for torpedo bombing?
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I would imagine that in a project like this, even to get it working approximately would be a great achievement. </p>
  
I don't remember.<br> <br> '''Nebeker: ''' It may have just set the dials differently.<br> <br> '''Townes: '''
+
<p>'''Townes: ''' </p>
  
I really don't remember. I must have been asked to look into that, look into the possibility of torpedo bombing. <br> <br> '''Nebeker: '''
+
<p>Yes. Oh, sure. Well, we were thankful it was working. [Chuckling] We'd been working hard. We didn't know what was supposed to be good and what was supposed to be bad. We just did as much as we could in the kind of time available, and got it as accurate as we could with the kind of techniques we had. </p>
  
But that was not the main purpose of this? <br>  
+
<p>Somewhere in here, at some point, I think it was probably later than this, I actually did a statistical analysis of these errors in the system. My impression is that it was one of the very first times that anybody had tried to add up a lot of minor errors in a system to predict the overall performance of a system, just on a probability basis. I made measurements and estimates of all the errors and all the different kinds of parameters and elements. Then added it all up. I remember joking at the time, well, this is what the mathematics says it should be. [Chuckling] Of course nobody knows whether this kind of thing works out or not, but this is what the mathematics says it ought to be. Well, it turned out to work out quite well. That kind of systems analysis is common nowadays. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
No, no, we never did any actual torpedo bombing.<br> <br> '''Nebeker: '''
+
<p>But they weren't then? </p>
  
I see. <br> <br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
As I say, I must have been asked to look into it.<br> <br> '''Nebeker: '''
+
<p>Nobody that I know else had done then. They all seemed to ignore it. Nor did they want to trust it very far. [Chuckling] </p>
  
A couple of pages further on page 140 you've got a heading "Second Derivation of Torpedo Bombing Equation." So you're working out what the calculator in the computer would have to do for torpedo bombing. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>It sounds like something that Sid Darlington would take to. </p>
  
Yes, yes. Right. We must have been asked to look at that. Maybe we just thought it could be useful and started doing it. I don't remember anything about it, so I guess nothing ever happened. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes. Well, Sid, I think, was ready to believe it. </p>
  
Well, it went a little bit further. On the next page you've actually sketched the circuit for torpedo bombing. <br> <br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
That's the system. I see. <br>  
+
<p>The idea was that you have these estimates of all these individual errors for the different components of the system. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
And you've signed it and dated it.<br> <br> '''Townes: ''' I see. [Chuckling] <br>  
+
<p>Yes. Then you add the sum of squares, assuming Gaussian errors, which you don't know to be Gaussian, but nonetheless it is a first approximation. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
So it looks like it's your contribution. <br>  
+
<p>Then see what error distribution you have for the system as a whole? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Must have been. <br> <br> '''Nebeker: '''  
+
<p>That's right. That was the idea. Get the system error from the component errors. And it's now, very common. Everybody accepts it, everybody does it nowadays, if they're interested. But I think that was one of the first. I don't know of anybody else who was doing it at that time. But that was probably a year or two later than this. </p>
  
You don't recall its being built?<br> <br> '''Townes: '''
+
==== Torpedo bombing  ====
  
No, I don't recall its being built. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Or page 130 or another page or two there's a geometry of torpedo bombing. Was that a special version of this computer for torpedo bombing? </p>
  
There's a second torpedo bombing circuit. So these are the last pages of that notebook that I copied. There's an air speed meter. You've got some notes on behavior of plane in rough weather. Pitch and roll. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I don't remember. </p>
  
Yes. Right. Must have correction with thermistor circuit.
+
<p>'''Nebeker: ''' </p>
  
==== Bell Labs work environment  ====
+
<p>It may have just set the dials differently. </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
You said that you didn't have much contact after the first period with Lovell's group.<br> <br> '''Townes: '''
+
<p>I really don't remember. I must have been asked to look into that, look into the possibility of torpedo bombing. </p>
  
No. Not so much.<br> <br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
There must have been other groups there working on these kinds of analog computers. <br>  
+
<p>But that was not the main purpose of this? </p>
  
<br> '''Townes: ''' No. Well, I don't remember. I don't remember other groups. We continued to work all through the war, and we were in close contact with the Whippany gang. We worked quite closely with them. Lovell continued, as I remember, but it turned out we didn't need to have any special contact with him about other things. The potentiometers were going along reasonably. They were never terribly accurate or terribly flexible.<br> <br> '''Nebeker: '''
+
<p>'''Townes: ''' </p>
  
They were doing the job. <br>  
+
<p>No, no, we never did any actual torpedo bombing. </p>
  
 +
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>I see. </p>
  
We used them as they were. <br> <br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
What about the work environment? As I said, I've read about how short vacations were, something like an average of two days a year at Bell Labs during the war. And that it was common to work overtime and Saturdays. What about in your group? <br>  
+
<p>As I say, I must have been asked to look into it. </p>
  
<br> '''Townes: '''  
+
<p><br> '''Nebeker: ''' </p>
  
We worked quite hard. I can't remember the vacation situation at that time. I probably took some vacation. I don't know. I'd have to think about it. I just don't remember at the moment anything. But we certainly were working pretty intensively.  
+
<p>A couple of pages further on page 140 you've got a heading "Second Derivation of Torpedo Bombing Equation." So you're working out what the calculator in the computer would have to do for torpedo bombing. </p>
  
 +
<p>'''Townes: ''' </p>
  
 +
<p>Yes, yes. Right. We must have been asked to look at that. Maybe we just thought it could be useful and started doing it. I don't remember anything about it, so I guess nothing ever happened. </p>
  
Down in Florida where we were bombing and checking out the equipment, I was down there a moderate amount, coming and going. It was sort of a vacation in a way. Not always, but some of the time, my wife came down, and we had a child by then, a baby, and we would drop down and go on the beach. The plane was not always flying. Obviously the plane had to be taken care of from time to time, or something would break down. So we had a moderate amount of free time just from all of these days when we couldn't work. Some of the time I did some physics. Some of the time I did a lot of underwater swimming and diving, which was not common at that time at all. I got a kind of a faceplate so I could see underwater. There was no scuba diving at that time and no snorkeling. The result was that lobsters were very common just offshore, and I could go out and get a lobster anytime I wanted to. Lots of interesting fish.<br> <br> I wouldn't say that the work was all that oppressive. It was very intensive at times, and when the plane was working, we would do a lot of flying. Then repair the equipment in between times and fly again. So it was intensive at times, and yet there were also periods during that testing when you couldn't work. So we'd knock off, and I could do some other things. We would do something. I like natural history very much, and so does my wife. We'd go take a hike and look at birds or swim. I don't remember taking vacations, but very likely I took at least some vacations. And I can't tell you how hard I worked excepting that [Chuckling] I know I worked pretty hard.
+
<p>'''Nebeker: ''' </p>
  
==== Reaction to the atomic bomb and other military developments  ====
+
<p>Well, it went a little bit further. On the next page you've actually sketched the circuit for torpedo bombing. </p>
  
'''Townes:'''  
+
<p>'''Townes: ''' </p>
  
One thing I remember is that when the first atomic bomb was dropped, I was working. It was about midday Saturday, and I was working in a little hut in Whippany checking out some radar. I've forgotten what. But I remember this little hut, and I had a radio, and I heard that this bomb had been dropped. And it was an unknown kind of bomb that did a very powerful job. Well, I knew precisely what it was. A number of friends I had who had been working on the system were indiscreet enough to keep me posted on what was happening. I remember very well. And I said, "Well, I don't have to keep working today." So I shut down and went home. [Chuckling] So I was working on Saturday that day at least. I think it was fairly common. Even Saturday nights, and we were working hard. <br>  
+
<p>That's the system. I see. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
How closely did you follow the war itself?
+
<p>And you've signed it and dated it. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Quite closely. We, were directly concerned about the bombing effects and what they were doing and how successful or unsuccessful they were. Now I must say, none of our systems actually ever got used in the war. That was a disappointment to me, but to indicate to you how ready people were to help out--and I certainly was--after I had done this a couple of times, developed systems and they said, Yes, that's very nice. Now would you develop this kind of system? They always mainly wanted to go toward, shorter wavelength radars. I decided that maybe it would be more useful for me to just drop out and go over and be in the Eastern Theater. I was thinking I'd look into the possibility of going over and joining [General Joseph W.] Stilwell in China as some kind of technical assistant there. There was not a clear way where I could be a lot of help. But, I thought, maybe I ought to do that instead of working at Bell Labs and trying to build these things because they're not getting any use. My bosses then got wind of this, and they worked on me [Chuckling] very hard to stay. I didn't quite see the right kind of an opening there, so I said, Well, okay. I'll just keep on doing this.<br>  
+
<p>I see. [Chuckling] </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Had you been in communications at Bell Labs, it would have been easier to take such a position overseas.<br>  
+
<p>So it looks like it's your contribution. </p>
  
 +
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>Must have been. </p>
  
Yes. Perhaps so. If I'd tried hard I could have gotten a position alright. There were a lot of different factors involved, but I considered that quite seriously. I thought, maybe I really ought to be doing that rather than developing equipment at that point in the war. It was fairly late in the war. I was also kept on after the war. They wanted me to continue because we had systems in development which clearly were going to be used for airplanes, and they wanted them finished up. And Bell Laboratories was very eager for me to stay in that business. So I stayed on about six months after the war, and then they let me out on the basis that I'd found somebody to replace me, which they did. Wooldridge had been transferred immediately back into physics right after the war. But they'd left me in charge of doing the systems planning. Actually I should make this plain, too. That I think that after the first system, we were not in charge of the overall systems building planning in principle. There was a mechanical engineer, for example, at least in the latter part of the war, named Mottram, who was in charge.
+
<p>'''Nebeker: ''' </p>
  
==== <br>Manufacturing, testing, and reliability  ====
+
<p>You don't recall its being built? </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
What's the name?
+
<p>No, I don't recall its being built. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Mottram, M-O-T-T-R-A-M. He was a Bell Labs mechanical engineer, and he was in charge of seeing that the system was made and could be put into production. The Whippany people were in charge of the radar. We were in charge of designing and making a system that would work. Mottram didn't really understand the system very thoroughly. He was more of a production engineer. But we reported to him, and he was reasonable enough. We really did the design, but he just kind of looked after it to be sure that it would be manufacturable. He was in charge of the overall system, including the radar from that point of view. Now this first system, I guess we were completely in charge. But it was a prototype system. As we got closer to something that was likely go into production, then Bell Labs decided they ought to put a production engineer in charge.  
+
<p>There's a second torpedo bombing circuit. So these are the last pages of that notebook that I copied. There's an air speed meter. You've got some notes on behavior of plane in rough weather. Pitch and roll. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Can we look at the pages I've photocopied from the next notebook dated 28 October '42? Are these goals or achievements?<br>  
+
<p>Yes. Right. Must have correction with thermistor circuit. </p>
  
<br> '''Townes: '''
+
==== Bell Labs work environment  ====
  
"Items considered while at G.V." Now I don't know what G.V. is.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>You said that you didn't have much contact after the first period with Lovell's group. </p>
  
Maybe these are goals.
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>No. Not so much. </p>
  
I think those are probably goals. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>There must have been other groups there working on these kinds of analog computers. </p>
  
And then on the following page, further goals are added. The first 20 are things that you were working on. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>No. Well, I don't remember. I don't remember other groups. We continued to work all through the war, and we were in close contact with the Whippany gang. We worked quite closely with them. Lovell continued, as I remember, but it turned out we didn't need to have any special contact with him about other things. The potentiometers were going along reasonably. They were never terribly accurate or terribly flexible. </p>
  
Yes, these are a list of different items and goals. Now here I mention the accuracy to be expected.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>They were doing the job. </p>
  
Yes, I was just looking at that.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>We used them as they were. </p>
  
BTO. That means "bombing through overcast." Probable errors computed from memo. I wrote a memo, I guess. This sounds like a more preliminary thing and calculations I'd have made.
+
<p>'''Nebeker: ''' </p>
  
'''<br>Nebeker: '''
+
<p>What about the work environment? As I said, I've read about how short vacations were, something like an average of two days a year at Bell Labs during the war. And that it was common to work overtime and Saturdays. What about in your group? </p>
  
What is this on page 19?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p><flashmp3>143_-_townes_-_clip_12.mp3</flashmp3></p>
  
"Change of resistors to be expected during potting.... Data taken by Fay."
+
<p>We worked quite hard. I can't remember the vacation situation at that time. I probably took some vacation. I don't know. I'd have to think about it. I just don't remember at the moment anything. But we certainly were working pretty intensively. </p>
  
<br> '''Nebeker: '''  
+
<p>Down in Florida where we were bombing and checking out the equipment, I was down there a moderate amount, coming and going. It was sort of a vacation in a way. Not always, but some of the time, my wife came down, and we had a child by then, a baby, and we would drop down and go on the beach. The plane was not always flying. Obviously the plane had to be taken care of from time to time, or something would break down. So we had a moderate amount of free time just from all of these days when we couldn't work. Some of the time I did some physics. Some of the time I did a lot of underwater swimming and diving, which was not common at that time at all. I got a kind of a faceplate so I could see underwater. There was no scuba diving at that time and no snorkeling. The result was that lobsters were very common just offshore, and I could go out and get a lobster anytime I wanted to. Lots of interesting fish.I wouldn't say that the work was all that oppressive. It was very intensive at times, and when the plane was working, we would do a lot of flying. Then repair the equipment in between times and fly again. So it was intensive at times, and yet there were also periods during that testing when you couldn't work. So we'd knock off, and I could do some other things. We would do something. I like natural history very much, and so does my wife. We'd go take a hike and look at birds or swim. I don't remember taking vacations, but very likely I took at least some vacations. And I can't tell you how hard I worked excepting that [Chuckling] I know I worked pretty hard. </p>
  
What is potting?
+
==== Reaction to the atomic bomb and other military developments  ====
  
<br> '''Townes: '''  
+
<p>'''Townes:''' </p>
  
I think that's probably getting the resistors set in a plastic which then hardened around them. I think that's what it was. This must be possible changes when you did that. Problems of changing resistance.<br>  
+
<p><flashmp3>143_-_townes_-_clip_13.mp3</flashmp3></p>
  
<br> '''Nebeker: '''
+
<p>One thing I remember is that when the first atomic bomb was dropped, I was working. It was about midday Saturday, and I was working in a little hut in Whippany checking out some radar. I've forgotten what. But I remember this little hut, and I had a radio, and I heard that this bomb had been dropped. And it was an unknown kind of bomb that did a very powerful job. Well, I knew precisely what it was. A number of friends I had who had been working on the system were indiscreet enough to keep me posted on what was happening. I remember very well. And I said, "Well, I don't have to keep working today." So I shut down and went home. [Chuckling] So I was working on Saturday that day at least. I think it was fairly common. Even Saturday nights, and we were working hard. </p>
  
I see. Now we're in February of '43.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>How closely did you follow the war itself? </p>
  
Yes, here's offset bombing. Well, that's a complication we put in, because not all targets would show up on the radar. You'd want to look at one target but bomb another one. That's the offset bombing. So that was put in as a further component. The system got more and more complicated as we refined it. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Quite closely. </p>
  
And then on page 53: "Measurement Indicator for the Land Version of BTO." What's the difference between the over sea and over land versions?<br>  
+
<p><flashmp3>143_-_townes_-_clip_14.mp3</flashmp3></p>
  
<br> '''Townes: '''  
+
<p>We, were directly concerned about the bombing effects and what they were doing and how successful or unsuccessful they were. Now I must say, none of our systems actually ever got used in the war. That was a disappointment to me, but to indicate to you how ready people were to help out--and I certainly was--after I had done this a couple of times, developed systems and they said, Yes, that's very nice. Now would you develop this kind of system? They always mainly wanted to go toward, shorter wavelength radars. I decided that maybe it would be more useful for me to just drop out and go over and be in the Eastern Theater. I was thinking I'd look into the possibility of going over and joining [General Joseph W.] Stilwell in China as some kind of technical assistant there. There was not a clear way where I could be a lot of help. But, I thought, maybe I ought to do that instead of working at Bell Labs and trying to build these things because they're not getting any use. My bosses then got wind of this, and they worked on me [Chuckling] very hard to stay. I didn't quite see the right kind of an opening there, so I said, Well, okay. I'll just keep on doing this. </p>
  
I'm afraid I don't remember. I mentioned Shank and Elmendorf. Bob Shank was involved with radar, and Elmendorf also. They were a couple of radar people. They had different groups of radar people to work with us, and they worked with us a number of times. This was just a way of making a kind of little more complicated setup. I don't know about the land version. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Had you been in communications at Bell Labs, it would have been easier to take such a position overseas. </p>
  
A couple of pages further on, this one I was interested in. You've got things to check, and you have Newark. So there were some flights out of Newark?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes. Perhaps so. If I'd tried hard I could have gotten a position alright. There were a lot of different factors involved, but I considered that quite seriously. I thought, maybe I really ought to be doing that rather than developing equipment at that point in the war. It was fairly late in the war. I was also kept on after the war. They wanted me to continue because we had systems in development which clearly were going to be used for airplanes, and they wanted them finished up. And Bell Laboratories was very eager for me to stay in that business. So I stayed on about six months after the war, and then they let me out on the basis that I'd found somebody to replace me, which they did. Wooldridge had been transferred immediately back into physics right after the war. But they'd left me in charge of doing the systems planning. Actually I should make this plain, too. That I think that after the first system, we were not in charge of the overall systems building planning in principle. There was a mechanical engineer, for example, at least in the latter part of the war, named Mottram, who was in charge. </p>
  
Yes, we flew out of Newark testing the systems. We couldn't drop bombs on the Newark area but we could fly.<br>
+
==== Manufacturing, testing, and reliability  ====
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
You were actually dropping sandbags or something? <br>  
+
<p>What's the name? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Well, they were real bombs in shape. In shape they were real bomb casings, but they were filled with sand to bring the weight up to just what the bomb would ordinarily be. So they were mechanically, so far as their flight through the air was concerned, exactly like a real bomb.  
+
<p>Mottram, M-O-T-T-R-A-M. He was a Bell Labs mechanical engineer, and he was in charge of seeing that the system was made and could be put into production. The Whippany people were in charge of the radar. We were in charge of designing and making a system that would work. Mottram didn't really understand the system very thoroughly. He was more of a production engineer. But we reported to him, and he was reasonable enough. We really did the design, but he just kind of looked after it to be sure that it would be manufacturable. He was in charge of the overall system, including the radar from that point of view. Now this first system, I guess we were completely in charge. But it was a prototype system. As we got closer to something that was likely go into production, then Bell Labs decided they ought to put a production engineer in charge. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
You couldn't do that in the Newark area.
+
<p>Can we look at the pages I've photocopied from the next notebook dated 28 October '42? Are these goals or achievements? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
No. [Chuckling] Go over the city and drop sand on them. So we flew out of Newark to do a preliminary check before we went on down to Boca Raton, Florida.  
+
<p>"Items considered while at G.V." Now I don't know what G.V. is. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Nebeker:'''
+
<p>Maybe these are goals. </p>
  
Okay. Now that's July of '43. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I think those are probably goals. </p>
  
Now you see a pilot instruction: I tell him to hold the height within 10 feet, and the direction within a half degree. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>And then on the following page, further goals are added. The first 20 are things that you were working on. </p>
  
Here on pages 90 and 91 it's apparently some idea of yours that maybe was patentable since you have it witnessed.
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes, these are a list of different items and goals. Now here I mention the accuracy to be expected. </p>
  
Yes, yes. I guess that's right. Patentable way of refining the instrumentation and so getting better readings.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes, I was just looking at that. </p>
  
I just thought it was interesting that you were apparently doing some sensitive testing here in August of '42. With these different dates you've got on all these pages.
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>BTO. That means "bombing through overcast." Probable errors computed from memo. I wrote a memo, I guess. This sounds like a more preliminary thing and calculations I'd have made. </p>
  
Yes, yes. Precession rates, gyros. That's right.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>What is this on page 19? </p>
  
Do you recall this period?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>"Change of resistors to be expected during potting.... Data taken by Fay." </p>
  
I remember Bell, the person mentioned there. We did a lot of testing in the laboratory of precision of the equipment and behavior and stability in the servos and all of that. We checked the system out quite well in the laboratory as a system. Then we installed it in the plane. There were plenty of things to be worked out. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>What is potting? </p>
  
I was just noticing on page 94 that you have a test flight from 4:30 P.M. to 8:00 P.M. Three and a half hours. Were they typically that long?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I think that's probably getting the resistors set in a plastic which then hardened around them. I think that's what it was. This must be possible changes when you did that. Problems of changing resistance. </p>
  
Oh, yes. Let's see, we were bombing something off Key Largo then.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I see. Now we're in February of '43. </p>
  
Yes, see August 17th, two flights total seven hours. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''  
+
<p>Yes, here's offset bombing. Well, that's a complication we put in, because not all targets would show up on the radar. You'd want to look at one target but bomb another one. That's the offset bombing. So that was put in as a further component. The system got more and more complicated as we refined it. </p>
  
Yes, the bombing runs were fairly long. I see I mention Goss and Soffel. Soffel was a technician. Warnock was an Air Force representative who was there to see how it was coming out.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>And then on page 53: "Measurement Indicator for the Land Version of BTO." What's the difference between the over sea and over land versions? </p>
  
Was that unusual?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I'm afraid I don't remember. I mentioned Shank and Elmendorf. Bob Shank was involved with radar, and Elmendorf also. They were a couple of radar people. They had different groups of radar people to work with us, and they worked with us a number of times. This was just a way of making a kind of little more complicated setup. I don't know about the land version. </p>
  
No. Of course the pilots were Air Force test pilots, and they, in a sense, could tell the Air Force how we were coming. But they would send people from time to time to fly with us and see how it was coming out. That was not so unusual. One time we had a load of fairly high-level people--some Bell Labs people and some people from Washington--fly in our plane. The radar antenna housing got stuck. That is, you let the antenna down out of the body of the plane so the antenna could see out, and then you'd raise it back up where the antenna couldn't see in order to land. Well, it was let down, and we couldn't get it up. Everybody thought that all these bigwigs were going to have to jump. [Laughter] Oh, dear, what had we done now. All these older men, distinguished people, we were going to make them jump out of there.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>A couple of pages further on, this one I was interested in. You've got things to check, and you have Newark. So there were some flights out of Newark? </p>
  
Couldn't you land the plane anyway?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes, we flew out of Newark testing the systems. We couldn't drop bombs on the Newark area but we could fly. </p>
  
No, they said it was too dangerous. Too dangerous. So I managed to climb down in there with some wrenches and screwdrivers and get it fixed. It was generally motor-driven, you see, and it had gotten jammed, and they couldn't do a thing with it. [Chuckling] It was a heck of a job. Did it by hand and got it back up again. So we had visitors every once in a while. That was the most important group of people to ever visit us, though. [Laughter] Just the right time for something to happen.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>You were actually dropping sandbags or something? </p>
  
Well, we obviously can't go through all the different things you were doing, working on the system, but it helps me to get an idea of this work.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Well, they were real bombs in shape. In shape they were real bomb casings, but they were filled with sand to bring the weight up to just what the bomb would ordinarily be. So they were mechanically, so far as their flight through the air was concerned, exactly like a real bomb. </p>
  
Well, there were very extensive tests, as you can see. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>You couldn't do that in the Newark area. </p>
  
Do you remember the system as being fairly reliable?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>No. [Chuckling] Go over the city and drop sand on them. So we flew out of Newark to do a preliminary check before we went on down to Boca Raton, Florida. </p>
  
It was fairly reliable. Our primary difficulty was the tubes and the relays, especially the tubes.
+
<p>'''Nebeker:''' </p>
  
<br> '''Nebeker: '''
+
<p>Okay. Now that's July of '43. </p>
  
Would you test them separately?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>Now you see a pilot instruction: I tell him to hold the height within 10 feet, and the direction within a half degree. </p>
  
Oh, we'd check them on the ground. I checked them on the ground beforehand and individually checked all the tubes.
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Here on pages 90 and 91 it's apparently some idea of yours that maybe was patentable since you have it witnessed. </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I see.<br>  
+
<p>Yes, yes. I guess that's right. Patentable way of refining the instrumentation and so getting better readings. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
And then replace whatever ones were out of spec. <br>  
+
<p>I just thought it was interesting that you were apparently doing some sensitive testing here in August of '42. With these different dates you've got on all these pages. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Before every run you'd test all the tubes?
+
<p>Yes, yes. Precession rates, gyros. That's right. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Do you recall this period? </p>
  
We'd test the critical ones. I'd test the critical ones. It was sort of a zero test game check which you can do rather quickly. I would say the principal breakdowns generally were vacuum tubes, there we so many of them in the system.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I remember Bell, the person mentioned there. We did a lot of testing in the laboratory of precision of the equipment and behavior and stability in the servos and all of that. We checked the system out quite well in the laboratory as a system. Then we installed it in the plane. There were plenty of things to be worked out. </p>
  
How many would you guess were in this system?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I was just noticing on page 94 that you have a test flight from 4:30 P.M. to 8:00 P.M. Three and a half hours. Were they typically that long? </p>
  
I think we had something like seventy or a hundred tubes. It was my feeling that that was about the limit at the time.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Oh, yes. Let's see, we were bombing something off Key Largo then. </p>
  
There were also relays you said that gave some problems.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Yes, see August 17th, two flights total seven hours. </p>
  
There were relay problems. A relay sometimes would get stuck. There weren't as many relays, electromechanical relays. I don't think we had so many problems. I think the potentiometers worked fairly reliably.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes, the bombing runs were fairly long. I see I mention Goss and Soffel. Soffel was a technician. Warnock was an Air Force representative who was there to see how it was coming out. </p>
  
You had at least some servomechanisms for this system.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Was that unusual? </p>
  
Yes. Servomechanisms are primarily a question of getting them tuned up to the best performance and so on so they're stable.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>No. Of course the pilots were Air Force test pilots, and they, in a sense, could tell the Air Force how we were coming. But they would send people from time to time to fly with us and see how it was coming out. That was not so unusual. One time we had a load of fairly high-level people--some Bell Labs people and some people from Washington--fly in our plane. The radar antenna housing got stuck. That is, you let the antenna down out of the body of the plane so the antenna could see out, and then you'd raise it back up where the antenna couldn't see in order to land. Well, it was let down, and we couldn't get it up. Everybody thought that all these bigwigs were going to have to jump. [Laughter] Oh, dear, what had we done now. All these older men, distinguished people, we were going to make them jump out of there. </p>
  
What were they doing? We saw the one that was directing an antenna.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Couldn't you land the plane anyway? </p>
  
Yes. I'm a little hazy about this. But I there were potentiometers where you would servo the potentiometer to a given voltage, and then there would be another potentiometer on the same shaft, which would then do the calculating for you. There were several potentiometers on a given shaft. It wasn't that the potentiometer just turned, as a result of some external input, to a calculated position where it had to be and the potentiometer went there. It was servoed. Then another potentiometer on the same shaft did the additional calculation there and read off the voltage.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>No, they said it was too dangerous. Too dangerous. So I managed to climb down in there with some wrenches and screwdrivers and get it fixed. It was generally motor-driven, you see, and it had gotten jammed, and they couldn't do a thing with it. [Chuckling] It was a heck of a job. Did it by hand and got it back up again. So we had visitors every once in a while. That was the most important group of people to ever visit us, though. [Laughter] Just the right time for something to happen. </p>
  
Was there feedback with that first one to turn it until you got a certain reading?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Well, we obviously can't go through all the different things you were doing, working on the system, but it helps me to get an idea of this work. </p>
  
Oh, yes. That's right. Negative feedback. Suppose you have a linear potentiometer. It would be given a voltage that it had to match, and it would turn to that voltage and sit there. Then another potentiometer, which was not linear, would then read off certain voltages which came from somewhere else, and did this calculation. But we had a number of servos. Antennas were some of them. Potentiometers were others. I think that was probably about it.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Well, there were very extensive tests, as you can see. </p>
  
One could imagine with a complex system like this that it could be very frustrating, that it would be difficult to get everything functioning.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Do you remember the system as being fairly reliable? </p>
  
Yes, that's right. Well, it was complex for the time. But I knew it very thoroughly because I built most of it myself with few associates of course, but I was quite familiar with all of it. The servicing was not a severe problem, but it did take some attention. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>It was fairly reliable. Our primary difficulty was the tubes and the relays, especially the tubes. </p>
  
I don't know if there's more to say about all of these test runs. A new notebook starts there. "Averaging Circuit," it says. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Would you test them separately? </p>
  
Averaging circuit? On what page?<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Oh, we'd check them on the ground. I checked them on the ground beforehand and individually checked all the tubes. </p>
  
Page 108. I'm still at the back of the previous notebook. This is interesting. At the back of this notebook you have some of the results graphed. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I see. </p>
  
Oh, yes.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>And then replace whatever ones were out of spec. </p>
  
There is also, on the page before that, pictures of this target.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Before every run you'd test all the tubes? </p>
  
Yes, right. That was a target constructed there. Just a kind of reflector.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>We'd test the critical ones. I'd test the critical ones. It was sort of a zero test game check which you can do rather quickly. I would say the principal breakdowns generally were [[Electron (or Vacuum) Tubes|vacuum tubes]], there we so many of them in the system. </p>
  
Is that to make it a readily-seen radar target?
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>How many would you guess were in this system? </p>
  
'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
That's right. It had a wire screen on it. And as a corner reflector it has a characteristic that if you send a beam into it, the beam gets reflected back in the same direction rather than scattered in all directions. So that makes the beam quite intense. If you had just a radar scatterer like, let's say building, then you'd have some directions moderately intense, others weaker. <br>  
+
<p>I think we had something like seventy or a hundred tubes. It was my feeling that that was about the limit at the time. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes, I see.<br>  
+
<p>There were also relays you said that gave some problems. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
In this case it's like a cat's eye. You shine a beam of light into a cat's eye, and the cat's eye will send the beam right back to you. So the cat's eyes glow. They look like they're shining in the dark. This does the same thing, back along the same direction. That's a principle very much used in optics these days.<br>  
+
<p>There were relay problems. A relay sometimes would get stuck. There weren't as many relays, electromechanical relays. I don't think we had so many problems. I think the potentiometers worked fairly reliably. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Okay. I just thought that was interesting to see that.<br>  
+
<p>You had at least some servomechanisms for this system. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I see I got a photograph of it. I haven't seen these things in years. I'm kind of glad because it's interesting to see them again. <br>  
+
<p>Yes. Servomechanisms are primarily a question of getting them tuned up to the best performance and so on so they're stable. </p>
  
==== <br>Other radar bombing research groups  ====
+
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>What were they doing? We saw the one that was directing an antenna. </p>
  
I'm talking with Charles Townes in his office at Berkeley on the 15th of September 1992. This is Rik Nebeker.<br> I've copied these from the relevant case files at the Bell Labs archives.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Yes. I'm a little hazy about this. But I there were potentiometers where you would servo the potentiometer to a given voltage, and then there would be another potentiometer on the same shaft, which would then do the calculating for you. There were several potentiometers on a given shaft. It wasn't that the potentiometer just turned, as a result of some external input, to a calculated position where it had to be and the potentiometer went there. It was servoed. Then another potentiometer on the same shaft did the additional calculation there and read off the voltage. </p>
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
These of course are internal documents. You see AN/APQ-7, a memorandum written by Bob Shank. Now Bob Shank and Chuck Elmendorf worked together on another system. They were located in the Graybar Building on Varick Street, as I was with Llewellyn for a while. They were also developing radar and a radar bombing system, the AN/APQ-7 I think was theirs.
+
<p>Was there feedback with that first one to turn it until you got a certain reading? </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Nebeker: '''
+
<p>Oh, yes. That's right. Negative feedback. Suppose you have a linear potentiometer. It would be given a voltage that it had to match, and it would turn to that voltage and sit there. Then another potentiometer, which was not linear, would then read off certain voltages which came from somewhere else, and did this calculation. But we had a number of servos. Antennas were some of them. Potentiometers were others. I think that was probably about it. </p>
  
I see.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>One could imagine with a complex system like this that it could be very frustrating, that it would be difficult to get everything functioning. </p>
  
But we consulted back and forth. That was a rather simpler system, and these memoranda indicate that they had planned to possibly put some of our computing systems on their radar. They were primarily radar people, who adapted the radar to bombing. Whereas we were primarily working in bombing, computed bombing, and navigation and computing systems, and putting that on the radars, you see. They refer to our AN/APQ-10 for other forms of the computers such as the AN/APQ-10 type or UBS, these could be added with minimum amount of modifications at some later time to this. The APQ-10 was the one we were working on. The UBS was the "universal bomb site," we called it, which was to be both optical and radar and we also developed that. These are things that we were doing, and they were thinking of maybe having us adapt it to put it on their system.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes, that's right. Well, it was complex for the time. But I knew it very thoroughly because I built most of it myself with few associates of course, but I was quite familiar with all of it. The servicing was not a severe problem, but it did take some attention. </p>
  
This is a memorandum from the 19th of February '44. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I don't know if there's more to say about all of these test runs. A new notebook starts there. "Averaging Circuit," it says. </p>
  
'Forty-four, that's right. This is fairly late, and this is from Bob Shank. Now here's another one, and you see the people involved. Now there's Newhouse who was at Whippany and a radar man and in charge of the radars generally which we used, at least initially in the game.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Averaging circuit? On what page? </p>
  
Was this Model 2? <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Page 108. I'm still at the back of the previous notebook. This is interesting. At the back of this notebook you have some of the results graphed. </p>
  
Mod-2, yes, of the AN/APQ-7. That's those memoranda. That group was building still a different system but I'd say primarily it was a modest adaptation of a radar system that they had designed for bombing.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Oh, yes. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
We have some of these numbers. The early work you were doing was on apparently the DU150550 bomb site radar. Do you recall that number?
+
<p>There is also, on the page before that, pictures of this target. </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>Yes, right. That was a target constructed there. Just a kind of reflector. </p>
  
I never used those numbers very much. They may be official, and I may have had them in my notebook, but these were the names we used, the APQ-10 and the UBS and so on. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Is that to make it a readily-seen radar target? </p>
  
Now this was Case 24839. Yeah, this was the AN/APQ-7 case which is different from this.
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>That's right. It had a wire screen on it. And as a corner reflector it has a characteristic that if you send a beam into it, the beam gets reflected back in the same direction rather than scattered in all directions. So that makes the beam quite intense. If you had just a radar scatterer like, let's say building, then you'd have some directions moderately intense, others weaker. </p>
  
The Eagle radar as I remember was a radar to be put on the B-29 as I remember. I think the MIT group was involved in the Eagle radar also. That sort of thing is mentioned here. Eagle-type radar, it says here, I think.
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Yes, I see. </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
So your involvement in that was adapting some kind of a computing system to that radar?
+
<p>In this case it's like a cat's eye. You shine a beam of light into a cat's eye, and the cat's eye will send the beam right back to you. So the cat's eyes glow. They look like they're shining in the dark. This does the same thing, back along the same direction. That's a principle very much used in optics these days. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Okay. I just thought that was interesting to see that. </p>
  
That was the idea. We never actually did it. We discussed it. These are memoranda about our discussions. We never actually did that. We discussed it back and forth and looked into it in some detail and made some plans for it. This right here is a kind of a conference for getting ready for manufacture. Here's Newhouse again, the radar man, and Mottram who was a mechanical engineer, that was really in charge of getting us into production.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I see I got a photograph of it. I haven't seen these things in years. I'm kind of glad because it's interesting to see them again. </p>
  
Now this is October of '42. <br>
+
==== Other radar bombing research groups  ====
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yeah, this is earlier. I didn't realize Mottram was involved quite that soon. It may be that he wasn't really doing this system at that time, but was in another system and was an interested party. <br>  
+
<p>I'm talking with Charles Townes in his office at Berkeley on the 15th of September 1992. This is Rik Nebeker. I've copied these from the relevant case files at the Bell Labs archives. </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
It was February of '42 that we made the first test flights with the first system.  
+
<p>These of course are internal documents. You see AN/APQ-7, a memorandum written by Bob Shank. Now Bob Shank and Chuck Elmendorf worked together on another system. They were located in the Graybar Building on Varick Street, as I was with [[Frederick Llewellyn|Llewellyn]] for a while. They were also developing [[Radar|radar]] and a radar bombing system, the AN/APQ-7 I think was theirs. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
It was March of '41 that you started it, so just under a year to a working system.<br>  
+
<p>I see. </p>
  
<br> '''Townes:'''  
+
<p>'''Townes: ''' </p>
  
Yeah. That's right. This is October. We are onto another system by then.  
+
<p>But we consulted back and forth. That was a rather simpler system, and these memoranda indicate that they had planned to possibly put some of our computing systems on their radar. They were primarily radar people, who adapted the radar to bombing. Whereas we were primarily working in bombing, computed bombing, and navigation and computing systems, and putting that on the radars, you see. They refer to our AN/APQ-10 for other forms of the computers such as the AN/APQ-10 type or UBS, these could be added with minimum amount of modifications at some later time to this. The APQ-10 was the one we were working on. The UBS was the "universal bomb site," we called it, which was to be both optical and radar and we also developed that. These are things that we were doing, and they were thinking of maybe having us adapt it to put it on their system. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Okay. Is this a 3-centimeter system?
+
<p>This is a memorandum from the 19th of February '44. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Probably. Now we talk about the BTO, "bombing through overcast." That probably was a 3-centimeter system. You see these are just statements about the status of various units. To what extent were they ready to be made.  
+
<p>'Forty-four, that's right. This is fairly late, and this is from Bob Shank. Now here's another one, and you see the people involved. Now there's Newhouse who was at Whippany and a radar man and in charge of the radars generally which we used, at least initially in the game. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Your main involvement on that was again the computing system?  
+
<p>Was this Model 2? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Well, we did the intellectual design of the whole system, marrying the radar and the computer. But we did not directly design the radar. We were the systems people. We designed in detail the computing part, and hooked them up, and made some specifications about the radar. So it was the overall system, but the radar was a kind of an important subset that was done by radar people, generally people at Whippany. This is another kind of internal memorandum about what's involved and what parameters are involved and capabilities. These are how to make these potentiometers and the specifications for the potentiometers, the shaping of potentiometers. By then they were pretty standard, and we knew a good deal about them.  
+
<p>Mod-2, yes, of the AN/APQ-7. That's those memoranda. That group was building still a different system but I'd say primarily it was a modest adaptation of a radar system that they had designed for bombing. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Do you know if the work that your group did on these potentiometers was used by other groups?<br>  
+
<p>We have some of these numbers. The early work you were doing was on apparently the DU150550 bomb site radar. Do you recall that number? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I don't know. I don't know of any substantial use, beyond Lovell's group and our group, of this kind of computation. It was originated by Lovell, but we extended it substantially. We used it right on through the war, and the last system I worked on really was blocked out by MIT and then brought down to Bell Laboratories and developed. At the very end of the war and after the war, the last one I was working on--and that went in the B-52 eventually and was a standard piece of equipment--that had some of these techniques in it. I lost track then. I don't know what happened after that. And of course other kinds of computing began to come in. <br>  
+
<p>I never used those numbers very much. They may be official, and I may have had them in my notebook, but these were the names we used, the APQ-10 and the UBS and so on. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
But there was a short period there beginning in the war and lasting until the early 'fifties when analog computing was a big field.  
+
<p>Now this was Case 24839. Yeah, this was the AN/APQ-7 case which is different from this. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Well, I can't tell you too much about the history, particularly after I left the field shortly after the war. You know we were buried in our own thing, doing our own things. Certainly there were both mechanical analogs and electrical analogs, and we had combinations of all of them. We were inventing new combinations: various ways of loading the potentiometers, shaping the potentiometers, loading the potentiometers, using them in combination, to get more and more complicated functions. <br>  
+
<p>The Eagle radar as I remember was a radar to be put on the B-29 as I remember. I think the MIT group was involved in the Eagle radar also. That sort of thing is mentioned here. Eagle-type radar, it says here, I think. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Except for your contact with Lovell's group, you were pretty much working on your own on it?<br>  
+
<p>So your involvement in that was adapting some kind of a computing system to that radar? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I believe so. I don't remember anybody else who was doing anything close enough to this and importantly enough for us to worry about.  
+
<p>That was the idea. We never actually did it. We discussed it. These are memoranda about our discussions. We never actually did that. We discussed it back and forth and looked into it in some detail and made some plans for it. This right here is a kind of a conference for getting ready for manufacture. Here's Newhouse again, the radar man, and Mottram who was a mechanical engineer, that was really in charge of getting us into production. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
It wasn't a case of secrecy requirements making it unlikely that you'd learn about other work?
+
<p>Now this is October of '42. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
No, I don't think so. I think in this field people were fairly open. The Norden bombsight I mentioned was closed for a while until we were asked to make a system which combined optics and radar, and then they opened up the Norden bombsight.  
+
<p>Yeah, this is earlier. I didn't realize Mottram was involved quite that soon. It may be that he wasn't really doing this system at that time, but was in another system and was an interested party. </p>
  
<br>  
+
<p>It was February of '42 that we made the first test flights with the first system. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
One radar engineer I talked to complained about the fact that during World War II often the same work was being done at maybe a research laboratory and Rad Lab because all that work was classified.  
+
<p>It was March of '41 that you started it, so just under a year to a working system. </p>
  
<br> '''Townes:'''  
+
<p>'''Townes:''' </p>
  
I did not see that aspect of it. The primary people we interacted with were at BTL and the MIT group. The MIT group I always felt was open though they were rivals; they were competitors of Bell Labs. But I felt that there was a good deal of trading back and forth of information. I never felt any secrecy problem there at all or any other hesitancy. Everybody was interested in the war, and while they were competing and everybody was trying to have the best ideas, nevertheless I didn't see any impediments to the trading of information for that reason. Now other companies, for example, let's say Raytheon, I'm sure did not share completely with Bell Labs for commercial reasons, and would deal in a more or less standard commercial way. We didn't see very much of the other commercial companies, excepting those from whom we were getting parts and supplies. The people who made the Norden bombsight we saw a good deal of. I remember seeing something of Minneapolis-Honeywell. They had some kind of navigation and bombing system. We went out to Minneapolis and looked at that and talked with them. I've forgotten just what happened there. <br>  
+
<p>Yeah. That's right. This is October. We are onto another system by then. </p>
  
 +
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>Okay. Is this a 3-centimeter system? </p>
  
Did you have contact with Western Electric? Did they do any of the work for things you were working on?<br>  
+
<p>'''Townes: ''' </p>
  
 +
<p>Probably. Now we talk about the BTO, "bombing through overcast." That probably was a 3-centimeter system. You see these are just statements about the status of various units. To what extent were they ready to be made. </p>
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Western Electric was the manufacturer for AT&amp;T at that time. If these things had ever been manufactured, they would have been made by Western Electric.<br>  
+
<p>Your main involvement on that was again the computing system? </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
But you didn't have contact with the production engineers there?
+
<p>Well, we did the intellectual design of the whole system, marrying the radar and the computer. But we did not directly design the radar. We were the systems people. We designed in detail the computing part, and hooked them up, and made some specifications about the radar. So it was the overall system, but the radar was a kind of an important subset that was done by radar people, generally people at Whippany. This is another kind of internal memorandum about what's involved and what parameters are involved and capabilities. These are how to make these potentiometers and the specifications for the potentiometers, the shaping of potentiometers. By then they were pretty standard, and we knew a good deal about them. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Do you know if the work that your group did on these potentiometers was used by other groups? </p>
  
Well, there were a few Western Electric personnel who had come in and looked at what we were doing, and talked about how it might be manufactured and tried to size it up. So they interacted with the Bell Labs people, but they were not systems designers. They were basically a manufacturing group, but they were interested in the fact that they might have to manufacture this, and how would it be done? And they looked at it and tried to evaluate it, and talked with us, and somewhat influenced our design from time to time as to what they could make, what their procedures were.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''  
+
<p>I don't know. I don't know of any substantial use, beyond Lovell's group and our group, of this kind of computation. It was originated by Lovell, but we extended it substantially. We used it right on through the war, and the last system I worked on really was blocked out by MIT and then brought down to Bell Laboratories and developed. At the very end of the war and after the war, the last one I was working on--and that went in the B-52 eventually and was a standard piece of equipment--that had some of these techniques in it. I lost track then. I don't know what happened after that. And of course other kinds of computing began to come in. </p>
  
I see. Did they tell you, That's going to be impossible to produce in numbers, that kind of a potentiometer?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>But there was a short period there beginning in the war and lasting until the early 'fifties when analog computing was a big field. </p>
  
I always put specifications on the systems and I remember one time when Walter McNair (Wooldridge's boss) came to me and said, "Well, Charlie, I really have to change and relax what you've done. The Western Electric people have said it would be very, very difficult. So I've opened up your specifications on that. I just had to do that." [Chuckling] No apology from this guy.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Well, I can't tell you too much about the history, particularly after I left the field shortly after the war. You know we were buried in our own thing, doing our own things. Certainly there were both mechanical analogs and electrical analogs, and we had combinations of all of them. We were inventing new combinations: various ways of loading the potentiometers, shaping the potentiometers, loading the potentiometers, using them in combination, to get more and more complicated functions. </p>
  
That's pretty interesting.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Except for your contact with Lovell's group, you were pretty much working on your own on it? </p>
  
So there was that kind of case where the manufacturers just felt that while something was possible, it was too difficult. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I believe so. I don't remember anybody else who was doing anything close enough to this and importantly enough for us to worry about. </p>
  
It's interesting to know that your group did get some input of that sort.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>It wasn't a case of secrecy requirements making it unlikely that you'd learn about other work? </p>
  
Yes. We did. This was the latter part of the war, and they were to be the manufacturers of those things.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>No, I don't think so. I think in this field people were fairly open. The Norden bombsight I mentioned was closed for a while until we were asked to make a system which combined optics and radar, and then they opened up the Norden bombsight. </p>
  
What about the rivalry you referred to? Were there groups at Bell Labs that you felt you were competing with?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>One radar engineer I talked to complained about the fact that during World War II often the same work was being done at maybe a research laboratory and Rad Lab because all that work was classified. </p>
  
I don't know. I don't think so. Take the Shank-Elmendorf group, for example, in some sense they were competitive. They were making another system. But I don't think they felt any difficulty about that. It was a simpler kind of a system, and they were radar people. They were good friends. We talked a lot about things.<br>  
+
<p>'''Townes:''' </p>
  
<br> '''Nebeker: '''  
+
<p>I did not see that aspect of it. The primary people we interacted with were at BTL and the MIT group. The MIT group I always felt was open though they were rivals; they were competitors of Bell Labs. But I felt that there was a good deal of trading back and forth of information. I never felt any secrecy problem there at all or any other hesitancy. Everybody was interested in the war, and while they were competing and everybody was trying to have the best ideas, nevertheless I didn't see any impediments to the trading of information for that reason. Now other companies, for example, let's say Raytheon, I'm sure did not share completely with Bell Labs for commercial reasons, and would deal in a more or less standard commercial way. We didn't see very much of the other commercial companies, excepting those from whom we were getting parts and supplies. The people who made the Norden bombsight we saw a good deal of. I remember seeing something of Minneapolis-Honeywell. They had some kind of navigation and bombing system. We went out to Minneapolis and looked at that and talked with them. I've forgotten just what happened there. </p>
  
Including the accuracy of your system?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Did you have contact with Western Electric? Did they do any of the work for things you were working on? </p>
  
Oh, yes. We talked.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Western Electric was the manufacturer for AT&amp;T at that time. If these things had ever been manufactured, they would have been made by Western Electric. </p>
  
Did you feel you were competing on that score?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>But you didn't have contact with the production engineers there? </p>
  
No, no. They were not in the same ball park in terms of complication of the function and the accuracy. But they were doing a useful job, and I would say while we were doing somewhat parallel things, there was a healthy interaction. I don't remember feeling any particular rivalry. The rivalry that I saw was primarily between Bell Labs and the MIT group. The MIT group was a pretty powerful group, and it was big with lots of good people. They had built some very simple bombing systems which actually got into use. They really started the radar bombing business so far as I know. It was a very, very simple kind of a system. Basically just fly in a straight line and use the radar for guidance. They were doing that, and that was in use. Then we went in for rather more complicated things, more precise things and more maneuverability. They were primarily still doing simple radar and bombing systems work. We were more complex and not as close to the war operations.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Well, there were a few Western Electric personnel who had come in and looked at what we were doing, and talked about how it might be manufactured and tried to size it up. So they interacted with the Bell Labs people, but they were not systems designers. They were basically a manufacturing group, but they were interested in the fact that they might have to manufacture this, and how would it be done? And they looked at it and tried to evaluate it, and talked with us, and somewhat influenced our design from time to time as to what they could make, what their procedures were. </p>
  
During the last of the war we were suddenly asked: "Well, would you redesign and build a system which MIT Laboratory had proposed and put together a demonstration in the lab at least?" That was a little bit of a blow, [Chuckling] because they had suddenly tried to jump ahead of us and do something still more advanced than we were doing, and had sold it to the military, and the military had said, "Well, of course, if we're going to have it manufactured, that ought to be AT&amp;T not Lincoln Laboratory." So they got us to redesign it for manufacture. It had to be pretty completely redesigned, but used some of their ideas. And they had some good ideas. That was the last system that I was involved with.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I see. Did they tell you, That's going to be impossible to produce in numbers, that kind of a potentiometer? </p>
  
Do you think you could identify that with what the case number was? You can see these different cases. This is the HAB X-band BTO, and this is the Eagle APQ. And you also worked on this, the AN/APQ-34 fairly late. I guess this was the last of these that you worked on.
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I always put specifications on the systems and I remember one time when Walter McNair (Wooldridge's boss) came to me and said, "Well, Charlie, I really have to change and relax what you've done. The Western Electric people have said it would be very, very difficult. So I've opened up your specifications on that. I just had to do that." [Chuckling] No apology from this guy. </p>
  
It had to be that one, then. It had to be that AN/APQ-34. It had to be that one that was the MIT one. That's the K-band.
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>That's pretty interesting. </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
It was this radar plus this system.  
+
<p>So there was that kind of case where the manufacturers just felt that while something was possible, it was too difficult. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
APQ-34, right. I think that must have been it. I think that must have been the one that originated at MIT.  
+
<p>It's interesting to know that your group did get some input of that sort. </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Nebeker: '''
+
<p>Yes. We did. This was the latter part of the war, and they were to be the manufacturers of those things. </p>
  
The AN/APQ-34. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>What about the rivalry you referred to? Were there groups at Bell Labs that you felt you were competing with? </p>
  
Yes. As I say, a sizeable group of people were put together to redesign that and check it out, and then get it to Western Electric in proper form for manufacture. I think that was it.<br>
+
<p>'''Townes: ''' </p>
  
==== <br>Uses of radar systems  ====
+
<p>I don't know. I don't think so. Take the Shank-Elmendorf group, for example, in some sense they were competitive. They were making another system. But I don't think they felt any difficulty about that. It was a simpler kind of a system, and they were radar people. They were good friends. We talked a lot about things. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
In the front of your notebook by this case number, you put GPI Model 1, Ground Position Indicator, Model 1.<br>  
+
<p>Including the accuracy of your system? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I'm a little hazy about this, but I think maybe the Ground Position Indicator was a sort of continuous calculation of coordinates as to where the plane was with respect to the ground. That's why it was called that. At the same time, this was a system which had moved us from the original wavelengths of 10 centimeters down to 1-1/4 centimeters. The 1-1/4 centimeters I was rather opposed to, and some of it I suppose was emotion. I was fed up with building something and having it changed by someone else.
+
<p>Oh, yes. We talked. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
And you could see the war was coming to a close.
+
<p>Did you feel you were competing on that score? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
That's right. And I thought, well, these things weren't really going to get into use. In addition to that, though, I recognized that this was a wavelength that could be absorbed by water.<br>  
+
<p>No, no. </p>
  
<br> '''Nebeker: '''
+
<p><flashmp3>143_-_townes_-_clip_15.mp3</flashmp3></p>
  
Van Vleck wrote a paper on it.  
+
<p>They were not in the same ball park in terms of complication of the function and the accuracy. But they were doing a useful job, and I would say while we were doing somewhat parallel things, there was a healthy interaction. I don't remember feeling any particular rivalry. The rivalry that I saw was primarily between Bell Labs and the MIT group. The MIT group was a pretty powerful group, and it was big with lots of good people. They had built some very simple bombing systems which actually got into use. They really started the radar bombing business so far as I know. It was a very, very simple kind of a system. Basically just fly in a straight line and use the radar for guidance. They were doing that, and that was in use. Then we went in for rather more complicated things, more precise things and more maneuverability. They were primarily still doing simple radar and bombing systems work. We were more complex and not as close to the war operations. </p>
  
<br>  
+
<p>During the last of the war we were suddenly asked: "Well, would you redesign and build a system which MIT Laboratory had proposed and put together a demonstration in the lab at least?" That was a little bit of a blow, [Chuckling] because they had suddenly tried to jump ahead of us and do something still more advanced than we were doing, and had sold it to the military, and the military had said, "Well, of course, if we're going to have it manufactured, that ought to be AT&amp;T not Lincoln Laboratory." So they got us to redesign it for manufacture. It had to be pretty completely redesigned, but used some of their ideas. And they had some good ideas. That was the last system that I was involved with. </p>
  
'''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Yes, I think I first woke up to that as a result of his paper I then read. In any case, he wrote a paper on it which was an informal memorandum really that was passed around. A very good memorandum that was passed around.  
+
<p>Do you think you could identify that with what the case number was? You can see these different cases. This is the HAB X-band BTO, and this is the Eagle APQ. And you also worked on this, the AN/APQ-34 fairly late. I guess this was the last of these that you worked on. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Where was he at the time?<br>  
+
<p>It had to be that one, then. It had to be that AN/APQ-34. It had to be that one that was the MIT one. That's the K-band. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
He was at Harvard, and he was working on noise and picking signals out of noise and things of this type. There was a Harvard group that was working on signal to noise problems and radio signals. He was a theoretical physicist, and somehow he ran into this and wrote a memorandum saying, "Well, this might possibly give trouble." That may have been the first time that I woke up to the problem. I read that with considerable interest, and then worked on it and tried to extend it and figure out how bad would it be, [Chuckling] and decided it was likely to be fairly bad.<br>  
+
<p>It was this radar plus this system. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Did you come up with estimates for the likely range of the radar signals?
+
<p>APQ-34, right. I think that must have been it. I think that must have been the one that originated at MIT. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>The AN/APQ-34. </p>
  
Yes, I did. I made estimates of what it was likely to be from basic physics, and I estimated the most likely amount of water in the air. I talked with people about it. The Bell Labs people said, "This is our assignment, and that's what we're supposed to do. And we'll have to talk to the Pentagon and Lincoln Laboratory." I talked with Rabi who was a big shot at the MIT Laboratory--I keep calling it Lincoln--the MIT Radiation Laboratory eventually became Lincoln. I talked with Rabi who was a big shot there, and Rabi just wouldn't listen. I talked with people down at the Pentagon a bit. They set it aside, and they didn't know how to answer it. I remember talking with a British officer who was stationed over here. And he said, "Well, jointly we've decided things. The United States had decided to go after the 1-1/4 centimeters. It's already decided, and, well, we just have to go ahead." I was still pretty young then, and people just didn't want to listen. [Chuckling]
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Yes. As I say, a sizeable group of people were put together to redesign that and check it out, and then get it to Western Electric in proper form for manufacture. I think that was it. </p>
  
I know one of the anticipated uses of these systems was for mortar location from the trajectory of a mortar. That requires a high resolution and relatively short range. So maybe this system would be useful.
+
==== Uses of radar systems ====
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Oh, well, I wouldn't say the K-band radar was useless. But for a bombing system it was.  
+
<p>In the front of your notebook by this case number, you put GPI Model 1, Ground Position Indicator, Model 1. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I see.  
+
<p>I'm a little hazy about this, but I think maybe the Ground Position Indicator was a sort of continuous calculation of coordinates as to where the plane was with respect to the ground. That's why it was called that. At the same time, this was a system which had moved us from the original wavelengths of 10 centimeters down to 1-1/4 centimeters. The 1-1/4 centimeters I was rather opposed to, and some of it I suppose was emotion. I was fed up with building something and having it changed by someone else. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
For a bombing system they had to have some range. That wasn't very useful. They were also going to put it on ships and longer-range things and all kinds of things. Well, it was just the rush of the time. It was a new field. People didn't know enough about it.<br>  
+
<p>And you could see the war was coming to a close. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Maybe there wasn't enough confidence in one or two physicists' calculations of the range.<br>  
+
<p>That's right. And I thought, well, these things weren't really going to get into use. In addition to that, though, I recognized that this was a wavelength that could be absorbed by water. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
That's right. It was all theoretical. Nobody had actually shown this; it was theoretical. But on the other hand, the theory was basically very sound. Anybody with knowledge about it couldn't really be in much doubt about it. It's sort of factor of two uncertainty, but not much more. The uncertainty is largely the broadening of the line, the shape of the line due to collisions in the air. How much would the sharpness of the line be decreased? So if it was broadened out, then it's not quite so severe. However, at that point Japan was becoming our main target and the air over the Pacific was known to be quite moist.  
+
<p>Van Vleck wrote a paper on it. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
But there were experimental results that supported this?
+
<p>Yes, I think I first woke up to that as a result of his paper I then read. In any case, he wrote a paper on it which was an informal memorandum really that was passed around. A very good memorandum that was passed around. </p>
  
==== <br>Spectroscopy and the K-band radar  ====
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Where was he at the time? </p>
  
There were experimental results on this in related spectroscopy, related spectroscopic results. One could make a rough estimate just from the size of a molecule; you can make a rough estimate. Rabi, as I said, didn't seem to want to listen to the argument. Nevertheless, during the latter part of the war, the Columbia Radiation Lab where Rabi was very influential made a big experiment to actually measure the shape of the water line. They had a big room resonator, resonating at 1-1/4 centimeters in multiple resonances. They had wet air and dry. Rabi was the head of that laboratory so that obviously he did, in the long run, [Chuckling] decide he'd better check up. They did some of the first work then in absorption of microwaves by a molecular line. It wasn't the very first work. The first work had been done before the war on ammonia at Michigan just from the point of view of a physics experiment. At Columbia, they measured the shape of the water line and at atmospheric pressure. All of that was part of the picture of my waking up to the potentiality of a microwave spectroscopy. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>He was at Harvard, and he was working on noise and picking signals out of noise and things of this type. There was a Harvard group that was working on signal to noise problems and radio signals. He was a theoretical physicist, and somehow he ran into this and wrote a memorandum saying, "Well, this might possibly give trouble." That may have been the first time that I woke up to the problem. I read that with considerable interest, and then worked on it and tried to extend it and figure out how bad would it be, [Chuckling] and decided it was likely to be fairly bad. </p>
  
Is that the first time you did serious work in that area, calculating absorption?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Did you come up with estimates for the likely range of the radar signals? </p>
  
I had done some spectroscopy in my thesis at Cal Tech. It wasn't a primarily spectroscopic thesis, but I'd done some spectroscopy.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''  
+
<p>Yes, I did. I made estimates of what it was likely to be from basic physics, and I estimated the most likely amount of water in the air. I talked with people about it. The Bell Labs people said, "This is our assignment, and that's what we're supposed to do. And we'll have to talk to the Pentagon and Lincoln Laboratory." I talked with Rabi who was a big shot at the MIT Laboratory--I keep calling it Lincoln--the MIT Radiation Laboratory eventually became Lincoln. I talked with Rabi who was a big shot there, and Rabi just wouldn't listen. I talked with people down at the Pentagon a bit. They set it aside, and they didn't know how to answer it. I remember talking with a British officer who was stationed over here. And he said, "Well, jointly we've decided things. The United States had decided to go after the 1-1/4 centimeters. It's already decided, and, well, we just have to go ahead." I was still pretty young then, and people just didn't want to listen. [Chuckling] </p>
  
That kind of spectroscopy?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I know one of the anticipated uses of these systems was for mortar location from the trajectory of a mortar. That requires a high resolution and relatively short range. So maybe this system would be useful. </p>
  
No, no. This was normal, visible spectroscopy. I'd taken a course in molecular spectroscopy at Cal Tech--essentially to get educated. But I was not in close contact with the field. But this got me interested, and as I started looking into it, I saw the potentialities more and more.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Oh, well, I wouldn't say the K-band radar was useless. But for a bombing system it was. </p>
  
Is it fair to say that if you hadn't worked on that K-band system that your interest in microwave spectroscopy might not have been awakened?
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>I see. </p>
  
'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I think that's quite right. That's what did it. I looked at it carefully enough that I saw the potentials, and otherwise I wouldn't have paid that much attention to it. I would have gone off in some other direction. Now maybe some other direction would have been fruitful, but on the other hand I certainly wouldn't have gone in that direction. No, that really started the whole thing. Of course the availability of K-band equipment was very important. It became very cheap, lots of it, and it had been developed pretty well. There were good local oscillators, klystrons, and waveguides and detectors. What really got me interested in microwave spectroscopy was looking carefully at the shapes of these lines and thinking about the theory. Since we didn't now much about the shapes of the lines, we had to look very hard at theoretical predictions. Van Vleck and Weisskopf had published a paper on spectral line shapes, and that was a very good basis for trying to understand them. But nobody had ever quite recognized that by going to lower pressure, the line just got narrower and narrower without getting weaker, and the center of the line stayed just as intense. The line simply got narrower. That was so surprising. In terms of any spectroscopic practice nobody had ever seen that. They'd pump gas down and found that the lines got weaker. That was the normal experience. That experience was primarily because the width of the lines was limited by the spectrometers, not by the molecules themselves. So the spectrometers have a certain width. As the line gets narrower, and you're looking at that full width, well, the total fraction of energy absorbed in that width keeps going down. <br>  
+
<p>For a bombing system they had to have some range. That wasn't very useful. They were also going to put it on ships and longer-range things and all kinds of things. Well, it was just the rush of the time. It was a new field. People didn't know enough about it. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
But if you had a better spectrometer, then right at the peak of the line it'd be just as intense. Well, nobody had ever experienced that, and they couldn't quite believe it. In fact, when I tried to sell the idea of working on this to Bell Labs, Jim Fisk, who was then head of the physics department, felt that it really couldn't be right. I argued with him about it, pointing out that's exactly what the theory said, and I don't think you can get around it. He then called on Arnold--oh, dear, I can't think of his name now. A theoretical physicist who had worked at Columbia and was familiar with their work on the water line. He'd transferred to Bell Labs, and Jim Fisk thought highly of him and trusted him. He said, Look, would you look into this thing and find out and tell me, can Charlie be right? And Arnold look at it and said, "Yeah, that seems right."<br>  
+
<p>Maybe there wasn't enough confidence in one or two physicists' calculations of the range. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Who was it who looked at it?<br>  
+
<p>That's right. It was all theoretical. Nobody had actually shown this; it was theoretical. But on the other hand, the theory was basically very sound. Anybody with knowledge about it couldn't really be in much doubt about it. It's sort of factor of two uncertainty, but not much more. The uncertainty is largely the broadening of the line, the shape of the line due to collisions in the air. How much would the sharpness of the line be decreased? So if it was broadened out, then it's not quite so severe. However, at that point Japan was becoming our main target and the air over the Pacific was known to be quite moist. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
[Chuckling] I'm trying to think of his name. It's a Scandinavian name, and his name is Arnold Nordsieck.
+
<p>But there were experimental results that supported this? </p>
  
<br>
+
==== Spectroscopy and the K-band radar  ====
  
I primarily mention that because it was waking up to this whole new field which most other people didn't realize was there. In fact, they largely doubted what was happening. That's completely because I got interested in looking into the problem. It's completely because of that. Otherwise I would not have awoken to that either.<br>  
+
<p>'''Townes: ''' </p>
  
==== System improvements  ====
+
<p>There were experimental results on this in related spectroscopy, related spectroscopic results. One could make a rough estimate just from the size of a molecule; you can make a rough estimate. Rabi, as I said, didn't seem to want to listen to the argument. Nevertheless, during the latter part of the war, the Columbia Radiation Lab where Rabi was very influential made a big experiment to actually measure the shape of the water line. They had a big room resonator, resonating at 1-1/4 centimeters in multiple resonances. They had wet air and dry. Rabi was the head of that laboratory so that obviously he did, in the long run, [Chuckling] decide he'd better check up. They did some of the first work then in absorption of microwaves by a molecular line. It wasn't the very first work. The first work had been done before the war on ammonia at Michigan just from the point of view of a physics experiment. At Columbia, they measured the shape of the water line and at atmospheric pressure. All of that was part of the picture of my waking up to the potentiality of a microwave spectroscopy. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Maybe we could look at these. There are not that many pages from these last couple of notebooks. You probably have copies in that folder there. The Notebook 19729, if we could start with that one because we went through the other ones yesterday. <br>  
+
<p>Is that the first time you did serious work in that area, calculating absorption? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Okay.<br>  
+
<p>I had done some spectroscopy in my thesis at Cal Tech. It wasn't a primarily spectroscopic thesis, but I'd done some spectroscopy. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
This is the HAB X-band BTO radar [case 24822-1]. There's more of this error analysis. You seem to have done a fair amount of that.
+
<p>That kind of spectroscopy? </p>
  
<br>'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yeah, well, that was important to us.  
+
<p>No, no. This was normal, visible spectroscopy. I'd taken a course in molecular spectroscopy at Cal Tech--essentially to get educated. But I was not in close contact with the field. But this got me interested, and as I started looking into it, I saw the potentialities more and more. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
I was also struck by some examples in these pages of your doing what today would be called numerical analysis. I don't see it right now, but I think that must have come up for a lot of physicists and engineers.
+
<p>Is it fair to say that if you hadn't worked on that K-band system that your interest in microwave spectroscopy might not have been awakened? </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''  
+
<p>I think that's quite right. That's what did it. I looked at it carefully enough that I saw the potentials, and otherwise I wouldn't have paid that much attention to it. I would have gone off in some other direction. Now maybe some other direction would have been fruitful, but on the other hand I certainly wouldn't have gone in that direction. </p>
  
I see in here some calculations I made for Bob Shank. I had business with Shank, and then I covered various things. He was worrying about some of these things.  
+
<p><flashmp3>143_-_townes_-_clip_16.mp3</flashmp3></p>
  
<br> '''Nebeker: '''
+
<p>No, that really started the whole thing. Of course the availability of K-band equipment was very important. It became very cheap, lots of it, and it had been developed pretty well. There were good local oscillators, [[Klystron|klystrons]], and waveguides and detectors. What really got me interested in microwave spectroscopy was looking carefully at the shapes of these lines and thinking about the theory. Since we didn't now much about the shapes of the lines, we had to look very hard at theoretical predictions. Van Vleck and Weisskopf had published a paper on spectral line shapes, and that was a very good basis for trying to understand them. But nobody had ever quite recognized that by going to lower pressure, the line just got narrower and narrower without getting weaker, and the center of the line stayed just as intense. The line simply got narrower. That was so surprising. In terms of any spectroscopic practice nobody had ever seen that. They'd pump gas down and found that the lines got weaker. That was the normal experience. That experience was primarily because the width of the lines was limited by the spectrometers, not by the molecules themselves. So the spectrometers have a certain width. As the line gets narrower, and you're looking at that full width, well, the total fraction of energy absorbed in that width keeps going down. </p>
  
These were better approximations.<br>  
+
<p>But if you had a better spectrometer, then right at the peak of the line it'd be just as intense. Well, nobody had ever experienced that, and they couldn't quite believe it. In fact, when I tried to sell the idea of working on this to Bell Labs, Jim Fisk, who was then head of the physics department, felt that it really couldn't be right. I argued with him about it, pointing out that's exactly what the theory said, and I don't think you can get around it. He then called on Arnold--oh, dear, I can't think of his name now. A theoretical physicist who had worked at Columbia and was familiar with their work on the water line. He'd transferred to Bell Labs, and Jim Fisk thought highly of him and trusted him. He said, Look, would you look into this thing and find out and tell me, can Charlie be right? And Arnold look at it and said, "Yeah, that seems right." </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
I see here's a kind of additional arrangement of potentiometers that we thought would give the kinds of functions approximately that one needed. So I was trying to advise Shank on some of the things he was doing even though I wasn't working with him directly. There's a cosine amplifier, I see. <br>  
+
<p>Who was it who looked at it? </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Can you explain what that is?<br>  
+
<p>[Chuckling] I'm trying to think of his name. It's a Scandinavian name, and his name is Arnold Nordsieck. </p>
  
<br> '''Townes: '''
+
<p>I primarily mention that because it was waking up to this whole new field which most other people didn't realize was there. In fact, they largely doubted what was happening. That's completely because I got interested in looking into the problem. It's completely because of that. Otherwise I would not have awoken to that either. </p>
  
Yes. [Chuckling] Well, we had a hard time approximating this particular function, as I remember.
+
==== System improvements  ====
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
The cosine function?<br>  
+
<p>Maybe we could look at these. There are not that many pages from these last couple of notebooks. You probably have copies in that folder there. The Notebook 19729, if we could start with that one because we went through the other ones yesterday. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes. And I don't remember just why. But somehow we couldn't build a potentiometer that approximated it sufficiently well. So what I did was to say, well, let's run the potentiometer along. Then when the voltage gets to a certain point, you put in a new resistor at a certain place which then modifies it and modifies the function. You keep putting in these additional resistors as you go along; then you can get any arbitrary function you want. Now how do you put in these new resistors? Well, as the voltage changes, you slip in a diode which cuts on or off. So this is an arrangement with a lot of different resistors and vacuum tube switches, which when you come to a certain voltage, this thing flips in, modifies the function, and then you can flip in something else. Obviously you go along, say, in time, and then you just flip in a batch of resistors, and you can get any arbitrary function you want.<br>  
+
<p>Okay. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
This is something like a hybrid between a digital and an analog computer?
+
<p>This is the HAB X-band BTO radar [case 24822-1]. There's more of this error analysis. You seem to have done a fair amount of that. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes, a bit like that. [Chuckling] That's right. Except that with the resistor then that carries out a certain slope in the curve. You're suddenly changing the slope in the curve, is what you're doing. <br>  
+
<p>Yeah, well, that was important to us. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
I see. So you're approximating this curve.<br>  
+
<p>I was also struck by some examples in these pages of your doing what today would be called numerical analysis. I don't see it right now, but I think that must have come up for a lot of physicists and engineers. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
It's a series of linear slopes, sort of.  
+
<p>I see in here some calculations I made for Bob Shank. I had business with Shank, and then I covered various things. He was worrying about some of these things. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
I see.  
+
<p>These were better approximations. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I remember some of my friends thinking I was a little bit crazy when I actually built it. They said, What? I said, it works. [Chuckling]
+
<p>I see here's a kind of additional arrangement of potentiometers that we thought would give the kinds of functions approximately that one needed. So I was trying to advise Shank on some of the things he was doing even though I wasn't working with him directly. There's a cosine amplifier, I see. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Why did they think it was crazy?  
+
<p>Can you explain what that is? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I think they thought that it was a little too complicated. Also, it was a new and additional complication for the potentiometers that they'd been working with.  
+
<p>Yes. [Chuckling] Well, we had a hard time approximating this particular function, as I remember. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
In other words, one potentiometer with the cosine.<br>  
+
<p>The cosine function? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
They doubted that I could get enough accuracy. By picking up just the right slopes and functions in a modest number of switches I did it, and they were easily impressed. [Chuckling] It really can be done.<br>  
+
<p>Yes. And I don't remember just why. But somehow we couldn't build a potentiometer that approximated it sufficiently well. So what I did was to say, well, let's run the potentiometer along. Then when the voltage gets to a certain point, you put in a new resistor at a certain place which then modifies it and modifies the function. You keep putting in these additional resistors as you go along; then you can get any arbitrary function you want. Now how do you put in these new [[Resistor|resistors]]? Well, as the voltage changes, you slip in a diode which cuts on or off. So this is an arrangement with a lot of different resistors and vacuum tube switches, which when you come to a certain voltage, this thing flips in, modifies the function, and then you can flip in something else. Obviously you go along, say, in time, and then you just flip in a batch of resistors, and you can get any arbitrary function you want. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Do you recall if this was actually put into any system?  
+
<p>This is something like a hybrid between a digital and an analog computer? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I don't know. I'm not at all sure we actually used it in the long run. I remember very well one of my friends who was a real doubter, and he was persuaded. I remember also I had a very bad case of poison ivy at the time. [Chuckling] I see that's some more potentiometer arrangements. <br>  
+
<p>Yes, a bit like that. [Chuckling] That's right. Except that with the resistor then that carries out a certain slope in the curve. You're suddenly changing the slope in the curve, is what you're doing. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
This is interesting. You've got some notes on APQ-10 tests. Do you think you took part in these tests? <br>  
+
<p>I see. So you're approximating this curve. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
I essentially always did do the testing. I took part in any tests. I wasn't there 100 percent of the time. I think by then Joe Burton was much involved in the tests, and the engineer Goss was involved in the early tests, though he tended to fade out later. Joe Burton may well have done some of these tests, but I'm sure I was down there part of the time.  
+
<p>It's a series of linear slopes, sort of. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
On the next page you have all of these 17 adjustments to be made to the system.  
+
<p>I see. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Adjustments and corrections to be made. Yes. I see that I've checked off some of them. Well, I'm still doing that kind of thing with our telescopes that I'm currently working with. [Chuckling] That's a list of all the things that need attention. <br>  
+
<p>I remember some of my friends thinking I was a little bit crazy when I actually built it. They said, What? I said, it works. [Chuckling] </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Or the next page you've got "Items To Be Done" which is quite a list down at the bottom of that page. <br>  
+
<p>Why did they think it was crazy? </p>
  
<br> '''Townes:'''  
+
<p>'''Townes: ''' </p>
  
Oh, yes.  
+
<p>I think they thought that it was a little too complicated. Also, it was a new and additional complication for the potentiometers that they'd been working with. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
This looks very typical sort of system engineering work.  
+
<p>In other words, one potentiometer with the cosine. </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
'''Townes: '''
+
<p>They doubted that I could get enough accuracy. By picking up just the right slopes and functions in a modest number of switches I did it, and they were easily impressed. [Chuckling] It really can be done. </p>
  
That's right. Again, this is not all that different from work I'm doing now, in a sense, on two telescopes used for interferometry in the infrared. They're much more complicated, and they use computers all over the place, of course. Nevertheless, they have checklists like this. [Chuckling] Lots of little things that need attention in the overall system. I remember that those were rather similar. I remember when I first proposed building a telescope because I had for some time been working in the laboratory just with rather simple, refined, but single elements and spectroscopy, and with lasers and so on. I had proposed this fairly complex telescope system to NSF. One of the reviews came back saying, "Well, can Townes build anything like that?" [Laughter] I guess he didn't know about my war work. There was a good deal of similarity. Any particular pages here that you want to discuss?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Do you recall if this was actually put into any system? </p>
  
I'm just flipping through this as well.
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I don't know. I'm not at all sure we actually used it in the long run. I remember very well one of my friends who was a real doubter, and he was persuaded. I remember also I had a very bad case of poison ivy at the time. [Chuckling] I see that's some more potentiometer arrangements. </p>
  
All this brings back memories. I see the flight to Memory Rock and then Banana River on the coast. "AFC fair on approach but oscillating on search. S.B. Greenbow." You asked me if we had many troubles. Well, this is a kind of list of troubles. Now of course those were manageable, but we still had to pay a good deal of attention. Radar range was very poor, radar was not performing as well as it might at that time. On the other hand, it was rare that we went out and didn't have a reasonably successful bombing, but it was never as good as I would have liked. There were always things to be improved. But the system was fairly functional.
+
<p>'''Nebeker: ''' </p>
  
<br> '''Nebeker: '''
+
<p>This is interesting. You've got some notes on APQ-10 tests. Do you think you took part in these tests? </p>
  
Was it the case that you were trying to get to some predetermined accuracy, improving the system until you got there? Or was it more a matter of getting reliable service out of the system?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>I essentially always did do the testing. I took part in any tests. I wasn't there 100 percent of the time. I think by then Joe Burton was much involved in the tests, and the engineer Goss was involved in the early tests, though he tended to fade out later. Joe Burton may well have done some of these tests, but I'm sure I was down there part of the time. </p>
  
It was a combination. We wanted as much accuracy as possible, but there was no cut-off point where it was good or it was bad. We tried to get as much accuracy as we could. We put in reasonable components and complications. In addition, we watched the serviceability of them. So it was a combination of the two.<br>  
+
<p>'''Nebeker: ''' </p>
  
==== <br>D-Day  ====
+
<p>On the next page you have all of these 17 adjustments to be made to the system. </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
The period we're looking at right now is April, May, June of '44. Of course D-Day was there on June 6th. Do you recall that day?
+
<p>Adjustments and corrections to be made. Yes. I see that I've checked off some of them. Well, I'm still doing that kind of thing with our telescopes that I'm currently working with. [Chuckling] That's a list of all the things that need attention. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
I don't recall so sharply the end of the European phase of the war. What I do recall, as I mentioned yesterday, is the dropping of the first bomb on Japan because I felt that.<br>  
+
<p>Or the next page you've got "Items To Be Done" which is quite a list down at the bottom of that page. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes:''' </p>
  
I thought maybe the announcement of the D-Day invasion might have seemed important.<br>  
+
<p>Oh, yes. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
Oh, I remember the invasion, of course. But then that lasted a while. No, I remember the invasion very well and the build-up to that. And there was a lot of talk about when it would happen.<br>  
+
<p>This looks very typical sort of system engineering work. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
I know there was hope that Germany would be knocked out of the war before the end of '44, which of course didn't happen. I'm just thinking this might have affected your attitude.<br>  
+
<p>That's right. Again, this is not all that different from work I'm doing now, in a sense, on two telescopes used for interferometry in the infrared. They're much more complicated, and they use computers all over the place, of course. Nevertheless, they have checklists like this. [Chuckling] Lots of little things that need attention in the overall system. I remember that those were rather similar. I remember when I first proposed building a telescope because I had for some time been working in the laboratory just with rather simple, refined, but single elements and spectroscopy, and with lasers and so on. I had proposed this fairly complex telescope system to NSF. One of the reviews came back saying, "Well, can Townes build anything like that?" [Laughter] I guess he didn't know about my war work. There was a good deal of similarity. Any particular pages here that you want to discuss? </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
I don't think so particularly. We still had a war to win, and the Japanese were pretty fierce, and that was a big job. Nevertheless, after Europe fell, it was clear we could concentrate more on Japan, and it had to come to the right end at that point. I felt that there was no chance that we would lose. Well, I felt that toward the latter part of the German period, that we were getting ahead. It was a matter of time. There'd still be a lot of sacrifice. But after Europe fell, why then there clearly was no doubt about the outcome. Nevertheless, the Japanese were so fierce that it was hard to say how long it was going to last and how many lives would be involved. I don't remember any kind of let-up on the part of anybody in that period because of those things. Various people differed in their dedication. Generally the country was pretty solidly behind the whole affair. Some people were making money on it; others were just sacrificing. Overall I think there was pretty much of a unity in the sense of being willing to put up with things until the war was over.  
+
<p>I'm just flipping through this as well. </p>
  
<br>  
+
<p>'''Townes: ''' </p>
  
==== Mechanical analog device  ====
+
<p>All this brings back memories. I see the flight to Memory Rock and then Banana River on the coast. "AFC fair on approach but oscillating on search. S.B. Greenbow." You asked me if we had many troubles. Well, this is a kind of list of troubles. Now of course those were manageable, but we still had to pay a good deal of attention. Radar range was very poor, radar was not performing as well as it might at that time. On the other hand, it was rare that we went out and didn't have a reasonably successful bombing, but it was never as good as I would have liked. There were always things to be improved. But the system was fairly functional. </p>
 +
 
 +
<p>'''Nebeker: ''' </p>
  
'''Nebeker: '''
+
<p>Was it the case that you were trying to get to some predetermined accuracy, improving the system until you got there? Or was it more a matter of getting reliable service out of the system? </p>
  
I had a question about page 74. It's talking about a system for the bombardier to determine ground speed. And the second paragraph reads: "However, since bombardier has to figure ground speed, probably okay to make him figure drift and ground speed on ABC computer." What is that?
+
<p>'''Townes: ''' </p>
  
<br> '''Townes: '''
+
<p>It was a combination. We wanted as much accuracy as possible, but there was no cut-off point where it was good or it was bad. We tried to get as much accuracy as we could. We put in reasonable components and complications. In addition, we watched the serviceability of them. So it was a combination of the two. </p>
  
I don't know what that is.
+
==== D-Day  ====
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
It looks like you're proposing a kind of slide rule system.<br>  
+
<p>The period we're looking at right now is April, May, June of '44. Of course D-Day was there on June 6th. Do you recall that day? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
We had a drift-distinguishing plane. That may be constructed to give tilt. <br>  
+
<p>I don't recall so sharply the end of the European phase of the war. What I do recall, as I mentioned yesterday, is the dropping of the first bomb on Japan because I felt that. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Is that 0.5o?<br>  
+
<p>I thought maybe the announcement of the D-Day invasion might have seemed important. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
It looks like 0.5o. Within half a degree perhaps?<br>  
+
<p>Oh, I remember the invasion, of course. But then that lasted a while. No, I remember the invasion very well and the build-up to that. And there was a lot of talk about when it would happen. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
I was just interested in that here you are devising a mechanical analog device.<br>  
+
<p>I know there was hope that Germany would be knocked out of the war before the end of '44, which of course didn't happen. I'm just thinking this might have affected your attitude. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Well, we were open-minded. Whatever worked. [Laughter] The optical people--the Norden site was completely optical-mechanical, generally relied more on mechanical things. It may be that I was trying to adapt it as quickly as possible. I had no aversion to mechanical systems. As I say, just whatever seemed to work was fine. We were willing to use any method possible. But I don't know what the ABC computer was. Might have been something like Automatic Bombing Control. I just don't know.<br>  
+
<p><flashmp3>143_-_townes_-_clip_17.mp3</flashmp3></p>
  
==== <br>Probable error calculations  ====
+
<p>I don't think so particularly. We still had a war to win, and the Japanese were pretty fierce, and that was a big job. Nevertheless, after Europe fell, it was clear we could concentrate more on Japan, and it had to come to the right end at that point. I felt that there was no chance that we would lose. Well, I felt that toward the latter part of the German period, that we were getting ahead. It was a matter of time. There'd still be a lot of sacrifice. But after Europe fell, why then there clearly was no doubt about the outcome. Nevertheless, the Japanese were so fierce that it was hard to say how long it was going to last and how many lives would be involved. I don't remember any kind of let-up on the part of anybody in that period because of those things. Various people differed in their dedication. Generally the country was pretty solidly behind the whole affair. Some people were making money on it; others were just sacrificing. Overall I think there was pretty much of a unity in the sense of being willing to put up with things until the war was over. </p>
  
'''Nebeker: '''
+
==== Mechanical analog device  ====
  
Okay. The following page has one of your more elaborate figures. Looking at all those different components of the system, if you look in the right column, you're giving the error at 2,000 feet.<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I had a question about page 74. It's talking about a system for the bombardier to determine ground speed. And the second paragraph reads: "However, since bombardier has to figure ground speed, probably okay to make him figure drift and ground speed on ABC computer." What is that? </p>
  
Yes, I see. This is a pretty complete tabulation. Well now, then I see finally a total of 30 units which gives 275 feet probable error, 13.3 mills at 20,000 feet. I think this was maybe the calculation where I had added up everything. And so far as I know it's the first time anybody'd tried this. Just add up everything as the square root of the sum of the squares.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>I don't know what that is. </p>
  
Is that how you arrived at the final probable error?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>It looks like you're proposing a kind of slide rule system. </p>
  
I think so. I looked at the estimated errors in each individual component.
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>We had a drift-distinguishing plane. That may be constructed to give tilt. </p>
  
Is there a theory that when you have a series of errors that the final error is the square of the sum of the squares?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Is that 0.5o? </p>
  
Probabilistically. That's not perfect of course. That's making some assumptions that each one is Gaussian and independent which clearly it isn't. On the other hand, that's about as good as you can do. You really don't know the distribution of each one. So that's the kind of thing that's normally done these days with almost any errors, as long as they're independent. So long as they're independent errors, why, you could almost always use that method if they're Gaussian. That's generally not a bad approximation. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>It looks like 0.5o. Within half a degree perhaps? </p>
  
Was that regarded as satisfactory, 275-foot probable error?<br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>I was just interested in that here you are devising a mechanical analog device. </p>
  
Yes, 13 mills was considered good. <br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>Well, we were open-minded. Whatever worked. [Laughter] The optical people--the Norden site was completely optical-mechanical, generally relied more on mechanical things. It may be that I was trying to adapt it as quickly as possible. I had no aversion to mechanical systems. As I say, just whatever seemed to work was fine. We were willing to use any method possible. But I don't know what the ABC computer was. Might have been something like Automatic Bombing Control. I just don't know. </p>
  
Is that the angular measurement?
+
==== Probable error calculations  ====
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
That's the angular. That mill is 1/1,000 of the altitude. Mill is a milliradian. That was the standard language which the bombardiers used. The mill error tends to be larger as you get lower in altitude because some of the errors were fixed in dimension rather than angle. So 13 mills at that altitude there, that's quite good. Or considered good at the time. Now 20 mills at 5000 or 10,000 feet was considered generally as good as one could expect to get. <br>  
+
<p>Okay. The following page has one of your more elaborate figures. Looking at all those different components of the system, if you look in the right column, you're giving the error at 2,000 feet. </p>
  
 +
<p>'''Townes: ''' </p>
  
 +
<p>Yes, I see. This is a pretty complete tabulation. Well now, then I see finally a total of 30 units which gives 275 feet probable error, 13.3 mills at 20,000 feet. I think this was maybe the calculation where I had added up everything. And so far as I know it's the first time anybody'd tried this. Just add up everything as the square root of the sum of the squares. </p>
  
By this time I knew the Norden bombsite quite well, and I knew it wasn't really all that good. It was a nice device for its time, but it wasn't terribly accurate. The biggest problem of all was that the poor pilots and bombardiers were sitting ducks up there if they operated in a time when they could see the ground and people would see them. They were required by the Norden to make a long straight run, and they were duck soup for anti-aircraft fire. The result was that they would try to come in as suddenly as they could, and they would probably drop their bombs before they should have, get out of the way, and try to dodge. The precision was probably much more affected by that behavior rather than the instrumentation itself. <br>  
+
<p>'''Nebeker: ''' </p>
  
 +
<p>Is that how you arrived at the final probable error? </p>
  
'''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Or the next page you talk about various ways of coordinating the Norden sight with this Ground Position Indicator system. The idea, I take it, is that one can rely either on the optical, the Norden system, or a radar system, as conditions allow.<br>  
+
<p>I think so. I looked at the estimated errors in each individual component. </p>
  
<br> '''Townes: '''  
+
<p>'''Nebeker: ''' </p>
  
That's right. Of course if you've got broad daylight, the Norden site could pick out a given object probably more precisely. Some objects don't give very good radar targets, and you have to do offset bombing which might be less accurate. So the optical pointing precision was clearly better when the optical conditions were right, and hence it was desirable to be able to use that. Now our system also allowed the plane to dodge around while guiding to stabilize the optics so that they would always point in the right direction. So we could continue to calculate and compute the wind speed as the pilot maneuvered around. Then at the last minute he could turn on. It was still dangerous to bomb in the daytime, but this was nevertheless a help to the bombardiers. <br>  
+
<p>Is there a theory that when you have a series of errors that the final error is the square of the sum of the squares? </p>
  
<br> '''Nebeker: '''  
+
<p>'''Townes: ''' </p>
  
Right. Do you know if that hybrid sort of system came into use during the war?
+
<p>Probabilistically. That's not perfect of course. That's making some assumptions that each one is Gaussian and independent which clearly it isn't. On the other hand, that's about as good as you can do. You really don't know the distribution of each one. So that's the kind of thing that's normally done these days with almost any errors, as long as they're independent. So long as they're independent errors, why, you could almost always use that method if they're Gaussian. That's generally not a bad approximation. </p>
  
<br>  
+
<p>'''Nebeker: ''' </p>
  
'''Townes: '''
+
<p>Was that regarded as satisfactory, 275-foot probable error? </p>
  
No. It came along after the war.
+
<p>'''Townes: ''' </p>
  
<br>  
+
<p>Yes, 13 mills was considered good. </p>
  
'''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
Okay.<br>  
+
<p>Is that the angular measurement? </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
This was December '44 we were working on it. Circuits for computation.<br>
+
<p>That's the angular. That mill is 1/1,000 of the altitude. Mill is a milliradian. That was the standard language which the bombardiers used. The mill error tends to be larger as you get lower in altitude because some of the errors were fixed in dimension rather than angle. So 13 mills at that altitude there, that's quite good. Or considered good at the time. Now 20 mills at 5000 or 10,000 feet was considered generally as good as one could expect to get. </p>
  
=== <br>Television  ===
+
<p><flashmp3>143_-_townes_-_clip_18.mp3</flashmp3></p>
  
'''Nebeker: '''
+
<p>By this time I knew the Norden bombsite quite well, and I knew it wasn't really all that good. It was a nice device for its time, but it wasn't terribly accurate. The biggest problem of all was that the poor pilots and bombardiers were sitting ducks up there if they operated in a time when they could see the ground and people would see them. They were required by the Norden to make a long straight run, and they were duck soup for anti-aircraft fire. The result was that they would try to come in as suddenly as they could, and they would probably drop their bombs before they should have, get out of the way, and try to dodge. The precision was probably much more affected by that behavior rather than the instrumentation itself. </p>
  
Now this is from another notebook actually, this one here. <br>  
+
<p>'''Nebeker: ''' </p>
  
<br> '''Townes: '''
+
<p>Or the next page you talk about various ways of coordinating the Norden sight with this Ground Position Indicator system. The idea, I take it, is that one can rely either on the optical, the Norden system, or a radar system, as conditions allow. </p>
  
Yes, I see. We jumped to '47.<br>  
+
<p>'''Townes: ''' </p>
  
<br> '''Nebeker: '''
+
<p>That's right. Of course if you've got broad daylight, the Norden site could pick out a given object probably more precisely. Some objects don't give very good radar targets, and you have to do offset bombing which might be less accurate. So the optical pointing precision was clearly better when the optical conditions were right, and hence it was desirable to be able to use that. Now our system also allowed the plane to dodge around while guiding to stabilize the optics so that they would always point in the right direction. So we could continue to calculate and compute the wind speed as the pilot maneuvered around. Then at the last minute he could turn on. It was still dangerous to bomb in the daytime, but this was nevertheless a help to the bombardiers. </p>
  
This is from your last notebook, and it's dated 2nd of August '47. Use of bombardment-induced conductivity for a television tube. This is apparently an idea you had for a new type of TV tube?
+
<p>'''Nebeker: ''' </p>
  
<br>  
+
<p>Right. Do you know if that hybrid sort of system came into use during the war? </p>
  
'''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Yes, I guess so. <br>  
+
<p>No. It came along after the war. </p>
  
<br> '''Nebeker: '''  
+
<p>'''Nebeker: ''' </p>
  
It goes on for three pages, and you've signed it and dated it at the end, although it doesn't seem to be witnessed. But it suggests that you might have thought of this as something that is worth looking into.<br>  
+
<p>Okay. </p>
  
<br> '''Townes: '''  
+
<p>'''Townes: ''' </p>
  
Right. Well, I had forgotten all about this, frankly. It's vaguely coming back to me now.  
+