Joseph Henry BiographyIn 1799, Joseph Henry was born in Albany, New York. He was educated at Albany Academy (now Princeton University). Intending to become a doctor, he studied natural sciences.
In 1824, Joseph Henry was employed as an assistant engineer on a survey team for a State road, three hundred miles long, between the Hudson River and Lake Erie. The experience changed the course of his career; he decided to study civil and mechanical engineering instead of medicine.
Work with MagnetsJoseph Henry's first discovery was that the power of a magnet could be immensely strengthened by winding it with insulated wire. He was the first person to make a magnet that could lift thirty-five hundred pounds of weight. Joseph Henry showed the difference between "quantity" magnets composed of short lengths of wire connected in parallel and excited by a few large cells; and "intensity" magnets wound with a single long wire and excited by a battery composed of cells in series. This was an original discovery, greatly increasing both the immediate usefulness of the magnet and its possibilities for future experiments.
Michael Faraday, William Sturgeon, and other inventors were quick to recognize the value of Joseph Henry's discoveries. Sturgeon magnanimously said, "Professor Joseph Henry has been enabled to produce a magnetic force which totally eclipses every other in the whole annals of magnetism; and no parallel is to be found since the miraculous suspension of the celebrated Oriental imposter in his iron coffin."
Self InductionJoseph Henry discovered the phenomena of self induction and mutual induction. In his experiment, a current sent through a wire in the second story of the building induced currents through a similar wire in the cellar two floors below.
TelegraphA telegraph was an early invention that communicated messages at a distance over a wire using electricity that was later replaced by the telephone. The word telegraphy comes from the Greek words tele which means faraway and grapho which means write.
The first attempts to send signals by electricity (telegraph) had been made many times before Joseph Henry became interested in the problem. William Sturgeon's invention of the electromagnet encouraged researchers in England to experiment with the electromagnet. The experiments failed and only produced current that weakened after a few hundred feet.
Basis For the Electric TelegraphHowever, Joseph Henry strung a mile of fine wire, placed an "intensity" battery at one end, and made the armature strike a bell at the other. Joseph Henry discovered the essential mechanics behind the electric telegraph.
This discovery was made in 1831, a full year before Samuel Morse invented the telegraph. There is no controversy as to who invented the first telegraph machine. That was Samuel Morse's achievement, but the discovery which motivated and allowed Morse to invent the telegraph was Joseph Henry's achievement.
In Joseph Henry's own words: "This was the first discovery of the fact that a galvanic current could be transmitted to a great distance with so little a diminution of force as to produce mechanical effects, and of the means by which the transmission could be accomplished. I saw that the electric telegraph was now practicable. I had not in mind any particular form of telegraph, but referred only to the general fact that it was now demonstrated that a galvanic current could be transmitted to great distances, with sufficient power to produce mechanical effects adequate to the desired object."
Magnetic EngineJoseph Henry next turned to designing a magnetic engine and succeeded in making a reciprocating-bar motor, on which he installed the first automatic pole changer, or commutator, ever used with an electric battery. He did not succeed in producing direct rotary motion. His bar oscillated like the walking beam of a steamboat.
Joseph Henry - Professor of Natural PhilosophyIn 1839, Joseph Henry was appointed as the Professor of Natural Philosophy at Princeton University. There he repeated his old experiments on a larger scale. He confirmed Steinheil's experiment of using the earth as return conductor, showed how a feeble current would be strengthened, and how a small magnet could be used as a circuit maker and breaker, the principles later used for the telegraph relay and the dynamo.
Joseph Henry - Researcher Vs InventorJoseph Henry was more of a researcher, rather than an inventor. He stated that "I never myself attempted to reduce the principles to practice, or to apply any of my discoveries to processes in the arts. My whole attention exclusive of my duties to the College, was devoted to original scientific investigations, and I left to others what I considered of subordinate importance, the application of my discoveries to useful purposes in the arts."
Joseph Henry was also uninterested in applying for any patents.
Smithsonian InstitutionThe Smithsonian Institution was founded in Washington in 1846, and Joseph Henry was its chief executive officer until his death in 1878.
Joseph Henry - Other AchievementsJoseph Henry made meteorology into a science and made the first weather map. He issued forecasts of the weather based upon definite knowledge rather than upon signs. He improved maritime lights and fog signals today.
Joseph Henry advised Alexander Graham Bell, when Bell first had the idea that electric wires might be able carry the human voice. Henry encouraged Bell to proceed with his experiments.
Alexander Graham Bell wrote that Joseph Henry thought Bell's ideas were the beginning of a great invention. Bell told Henry that he faced mechanical difficulties and that he lacked the electrical knowledge necessary to overcome those difficulties. Joseph Henry's advise was "Get It!"