Joseph Henry

The Albany Academy, Albany, NY

Joseph Henry
Joseph Henry

On April 27, 2007, John Rigden, Chair of the APS Historic Sites Committee, presented  the Albany Academy in Albany, NY with a plaque to honor physicist Joseph Henry for his pioneering work performed there on electromagnetism, in particular the discovery of self-inductance.

Henry was acknowledged as the inventor of the electric motor, the father of daily weather forecasts, and the preserver of the Smithsonian. He was so revered that the government closed for his funeral on May 16, 1878, a funeral attended by the President, Vice-President, the Cabinet, the members of the Supreme Court, Congress, and the senior officers of the Army and the Navy.

During his time, Henry was thought of as the successor to Benjamin Franklin in his experiments on electromagnetism. His scientific career began when he picked up and read the book Popular Lectures on Experimental Philosophy, Astronomy, and Chemistry when he was sixteen. Fascinated by this glimpse of science, he resolved to learn more.

Most of Henry’s research and contributions to science occurred at Albany Academy, where he enrolled in 1819. In his day it offered him the equivalent of a college education though we would see it today as closer to secondary school. Henry went beyond the coursework, avidly reading books in every area of science and many other fields. He supported himself by working as a schoolmaster then tutor, road surveyor to finally Professor of Mathematics and Natural Philosophy at the Albany Academy.

At the Albany Academy, his research centered on experiments with magnetism. He was the first to coil insulated wire tightly around an iron core in order to make an extremely powerful electromagnet. Using this technique, he built the most powerful electromagnet at the time for Yale. He also showed that, when making an electromagnet using just two electrodes attached to a battery, it is best to wind several coils of wire in parallel, but when using a set-up with multiple batteries, there should be only one single long coil. The latter made the telegraph feasible.

He continued to improve on devices with his research and, in 1831, created one of the first machines to use electromagnetism for motion. This was the earliest ancestor of modern DC motor. It did not use rotating motion for power, but was merely an electromagnet perched on a pole, rocking back and forth.

In the relatively isolated environment of the Albany Academy, Henry discovered the fundamental property of self-inductance. However, the British scientist Michael Faraday discovered it as well at about the same time, and, being first to publish his results, became the officially recognized discoverer of the phenomenon.

Henry left the Albany Academy for Princeton in 1832, and then became the Secretary of the brand new Smithsonian Institution in 1846. His job was to give scientific advice to the government and to make sure the Institution remained a research center as well as a museum. In the spring of 1863 Henry became one of the founding members of the National Academy of Science, and served as Academy president beginning in 1867. He served as both the National Academy of Science president and secretary of the Smithsonian Institution until his death in 1878. In 1893 his name was given to the standard electrical unit of inductive resistance, the henry.