Born: 17 December 1797
Died: 13 May 1878
Joseph Henry was born in 1797 to William and Ann Alexander Henry in Albany, New York. At age seven he was sent to live on his uncle’s farm, but quickly found his way to the village library. When his father died in 1814, Joseph returned to Albany. He took night classes to learn more about science, tutoring private students to earn his tuition. In 1826, he entered academic life as a professor of mathematics and physics at Albany Academy. There his methods of teaching science through demonstrations as well as his lectures made him a popular teacher. He also began to make his name in the scientific world by making more powerful magnets.
While teaching, Henry also experimented with electromagnetic engines and converting magnetism into electricity, a process known as induction. The unit of the rate of change of current per second was designated the “henry” in his honor. Henry never tried to patent his discoveries—not even the system of successive electromagnetic circuits that later became the basis of Samuel Morse’s telegraph. In 1832 he accepted a position at Princeton University as the chair of natural philosophy. For the first time, he had his own laboratory for year-round research. He was also inspired by a trip to Europe and a meeting with Michael Faraday, whose experiments closely paralleled his own.