Joseph Henry ( born Joseph Henry ; December 17, 1797 - May 13, 1878 ) - American physicist , first secretary of the Smithsonian Institution . Henry was considered one of the greatest American scientists since the days of Benjamin Franklin . By creating magnets, Henry discovered a new phenomenon in electromagnetism - self-induction . Regardless of Faraday, Henry discovered a mutual induction , but Faraday had previously published his results. His work on electromagnetic relays was the basis for the electric telegraph invented by Samuel Morse and Charles Wheatstone independently of Henry.
| Joseph Henry | |
|---|---|
| Joseph Henry | |
 | |
| Date of Birth | December 17, 1797 |
| Place of Birth | Albany ( New York , USA ) |
| Date of death | May 13, 1878 (aged 80) |
| Place of death | Washington (USA) |
| A country |  USA |
| Scientific field | Physics |
| Place of work | Princeton University Smithsonian Institution |
| Alma mater | |
| Known as | Electromagnetic induction researcher |
Henry was one of the first 50 outstanding scientists included by President Lincoln in the National Academy of Sciences of the USA (1863), and from 1868 until the end of his life he was its permanent president. In honor of Joseph Henry, the inductance unit in the International System of Units (SI) is named “ Henry ”.
Content
Biography
The early years
Joseph Henry was born December 17, 1797 , in the city of Albany ( New York State ). His parents were poor. Joseph lost his father early. In the remaining years of his childhood, Joseph lived with his grandmother in Galway ( Galway ; New York State). He was sent to a school, which was later renamed in his honor: “Elementary School named after Joseph Henry. " After school, he worked in a department store, and later, at 13, an apprentice with a watchmaker. Henry's first great love was theater, and he practically became a professional actor. But at the age of 16, he developed an interest in science after accidentally reading the book “Popular Lectures on Experimental Philosophy”. In 1819, he entered , where he studied for free. He was so poor that even with free education he had to earn extra money by tutoring. Henry wanted to do medicine, but in 1824 he was appointed assistant engineer to oversee the construction of a bridge between the Hudson River and Lake Erie . From that moment he was absorbed in an engineering career.
At Albany Academy
Joseph Henry studied excellently (so much that he often helped his teachers teach), and in 1826 he was appointed professor of mathematics and natural philosophy at the Albany Academy. He performed some of his most significant studies in this new position. His curiosity about terrestrial magnetism led him to experiment with magnetism in general. He was the first to apply a new technology for creating an electromagnet using windings from an insulated wire wound around an iron core. Such electromagnets were built by William Sturgeon , but Sturgeon used a winding of bare wire. Using his technology, Henry created the most powerful electromagnet of the time. With his inherent skill, he created multi-turn electromagnets called “compacted”: in a relatively small area of the electromagnet, he placed up to 400 turns of silk-insulated copper wire connected to a separate battery. If you connect these "strands" of winding in parallel, then the current strength will increase markedly.
Henry invented the "multi-coil" winding, which allowed to significantly increase the lifting force of the electromagnet. He suggested placing up to ten such windings on an electromagnet - this is how the world's first technical samples of coils (called "bobbins") appeared. In the process of numerous experiments, he changed the number and circuit of connecting coils to two galvanic batteries and managed to create “power” electromagnets with fantastic lifting force - from 30 to 325 kg with a dead weight of 10 kg magnet.
The striking range of Henry's scientific experiments. After the well-known experiments of Faraday, who had proved back in 1821 the rotation of the conductor around a magnet and a magnet around the conductor, in 1831 he created a model of an electric motor with a swinging motion - an “electromagnet-rocker arm” that made uniform swings. And although Henry considered his invention only a “physical toy”, he hoped that with further improvement this invention could have practical application. In the model built by the scientist, the electromagnet made 75 swings per minute, and the engine power was only 0.044 watts. Therefore, there was no question of its practical application.
In the same 1831, S. Dal Negro proposed an electric motor with an oscillating movement of the armature between the poles of a magnet. In the models of electric motors Henry and Dal Negro, the principle of reciprocating motion was used. The steam engine worked on the same principle. The following survivors speak of the exceptional vitality of this idea: the first inventors of the steamboat proposed using a steam engine to propel the oars in order to replace the rowers. And the first inventors of the engine wanted to create a moving mechanism that mimics the movement of the horse's legs.
Ballooning
Room Acoustics
Recent years
As a well-known scientist and director of the Smithsonian Institution, many young scientists and inventors turned to Henry, seeking his advice. Henry was condescending, friendly, restrained, with gentle humor. One such visitor was Alexander Bell , who wrote a letter on March 1, 1875, and introduced himself to Henry. Henry showed interest in Bell's experimental apparatus, and the next day Bell came to visit him. After the demonstration, Bell mentioned his untried idea of how to transmit human speech using electricity using a “harmonica-type apparatus,” which will have several steel tongues tuned to different frequencies to cover a person’s voice spectrum. Henry told Bell that he had a "sprout of great invention." Henry did not recommend Bella to publish his ideas until he perfected the invention. When Bell complained that he did not have the necessary knowledge, Henry resolutely said: “So master them!”
On June 25, 1876, Bell's experimental telephone (of a different design) was on display at the Centennial Exhibition in Philadelphia, at which Henry was one of the experts in the electrical exposition. On January 13, 1877, Bell showed his devices to Henry at the Smithsonian Institution, and Henry invited Bell to show them again that very evening at the Washington Philosophical Society. Henry praised the "value and amazing properties of Bell's discoveries and inventions."
Henry has been a member of the State Council for Lighthouses since 1852. In 1871, he was appointed chairman of the Council, and served in this post until the end of his days. Henry was the only civilian chairman. The United States Coast Guard honored Henry, and to his credit for the lighthouses and the acoustic fog lights, he was named after the boat, which was usually called Joe Henry . He was launched in 1880 and was in active service until 1904.
Henry died on May 13, 1878, and was buried at Oak Hill Cemetery in Washington.
Career
- 1826 - Professor of Mathematics and Natural Philosophy at Albany Academy (New York State)
- 1832 - Professor at Princeton
- 1835 - invents the electromechanical relay
- 1846 - First Secretary of the Smithsonian Institution , until 1878
- 1848 - Edits a book by G. Squire and E. Davis "Ancient Monuments of the Mississippi Valley" - the first publication of the institute.
- 1852 - elected to the State Council for Lighthouses
- 1871 - appointed Chairman of the Lighthouse Council
- From 1868 to the end of his days, he was the second president of the US National Academy of Sciences .
See also
- Electrodynamics
- Henry (unit)
- Chronology of inventions of mankind
- Timeline of information and communication technologies
Links
- Temples Yu.A. Henry (Henry) Joseph // Physicists: Biographical Reference / Ed. A.I. Akhiezer . - Ed. 2nd, rev. and add. - M .: Nauka , 1983 .-- S. 79 .-- 400 p. - 200,000 copies. (in per.)
- http://www.connect.ru/article.asp?id=3891
- http://www.krugosvet.ru/articles/04/1000454/1000454a1.htm
- http://www.ref.by/refs/88/19780/1.html
- The Joseph Henry Papers Project