Electromagnets Joseph Henry

Famous Joseph Henry (Joseph Henry) primarily to the fact that, fascinated by the "secrets" of electromagnetism, was the creator of the unique powerful electromagnets to lift the fantastic - from 30 up to 1500 kg at a body weight of 10 kg magnet. One of his magnets, created in 1831, able to lift 1,000 kg now it is stored in the Smithsonian Institution in Washington.

In general, the Joseph Henry was a very versatile scientist and interested in him were not only powerful electromagnets. I think many readers of the blog will be interesting to get acquainted with the biography of this extraordinary man

Joseph Henry was born in Albany (NY). As a child, Joseph Henry did and did not intend to become a physicist and inventor. After leaving school in Galway, he studied at the Academy of the evening in Albany, intending to become a doctor, but he showed a talent experimenter, and engaged in the Academy, he assisted in conducting chemical experiments. During the summer holidays he worked on the construction of the road between Kingston and Lake Erie. In 1826, Henry was appointed an instructor in mathematics and science at the Academy in Albany, and soon began to conduct experiments with electromagnets.

The results of experiments he concluded in his paper "Some modifications of the electromagnetic device," which read in Olbenskoy Academy in 1827, earning a reputation as an outstanding experimenter. Silk wedding dress from his wife, he insulated electric conductors, winding it in several layers of thoroughly and thereby increasing the strength of the electromagnet, giving it the well-known current configuration.

After he succeeded in 1830, the hard work, using one long and several short wires, to determine the optimal size of the magnet and the batteries needed for maximum effect. This was the first demonstration of Ohm's theory of the need to include the corresponding resistance in some parts of the electrical circuit.

Its connected in parallel magnets caused great interest. The strongest of them kept the weight of 3500 pounds (about 1575 kg). In 1831, Henry held the wire length of 1 mile (1,609.3 m) on its audience, and when he used a strong magnet and a suitable battery, a call to the other end of the conductor rang. This was the first demonstration of the telegraph with an audible signal.

In the same year he designed the model of the motor with a swinging motion "electromagnet-rocker" who performed 75 uniform oscillations per minute. And although his movement was soon return than rotational, he still solved the problem of converting electrical energy into mechanical energy.

One of the first electromagnets created by Joseph Henry in 1831

Opening of mutual induction phenomenon independently attributed to Michael Faraday and Henry, but Henry was irresponsible unhurried when publishing the results of the experiments, and the first Faraday said of his success. Finally, the priority of the discovery of mutual induction was given by Faraday, and Henry - discovery of the phenomenon of self-induction, which he described in the same article that the phenomenon of induction - in 1832

In 1832, when he was already a recognized scholar, Henry was invited to the post of Professor of Natural Sciences at the College of New Jersey (now the Princeton University), where he continued his study of electromagnetism. Henry found the first oscillatory nature of the spark discharge of the capacitor, which was estimated at its true worth only half a century later, at the dawn of telecommunications and radio. The lectures for the American Philosophical Society, he told about the invention of the electric relay, non- inductive coil and the possibility for an appropriate choice of turns to increase or decrease the voltage, which was the basis for the creation of the transformer, ie. E., Discoveries and inventions made by Joseph Henry underlie absolute work most electrical devices

He later described the change in inductance between individual coils, inductance effects at a distance, and the oscillating nature of the electrical discharge of the Leyden jar - a set of discoveries that were vital for the emergence of wireless telegraphy and radio.

It is interesting that in 1835. Henry in his lab demonstrated the first electric telegraph. He conveyed a message by wire to an adjacent building. But again, Henry, as in the case of Faraday, summed modesty. He did not publish his results, and the inventor of the telegraph is now considered by Samuel Morse, who invented it 2 years later. At the same time Morse (his engineering training was modest) did not hesitate to consult with Henry on the technical issues of the telegraph and then immediately patented what he sovetovalp Henry>

Henry held a number of research and other areas. For example, they have been carried out numerous meteorological observations.

By the 40 th years of the XIX century, Henry became the most authoritative American scientist. In 1846, he became secretary of the Smithsonian Institution. He not only performed official duties, but also organized the telegraphic Meteorological Agency, he was the first weather map and laid the foundations of scientific methods of weather forecasting.

Henry also made a lot of useful information for safety of navigation, its efforts were increased efficiency fog signals and beacons. Significant was his participation in various government projects, he discovered the many phenomena in acoustics and testing of building materials.

In 1868 he became president of the National Academy of Sciences, and remained so until the end of his life. In 1886 published a collection of his works entitled "Scientific works of Joseph Henry." Henry died on May 13, 1878 in Washington.

Scientific contribution to the treasury of knowledge, Henry received the highest praise: "Henry" was named in 1893 at the Electrotechnical Congress in Chicago inductance unit.

Useful links:

Joseph Henry in Wikipedia (in English. Lang.)

Materials of Joseph Henry Encyclopedia.com (on the Eng. Lang.)

Interesting article by Jan Shneiberg "Joseph Henry - great physicist America"

From the article: a quarter century and the whole epoch in the field of knowledge separated electrostatics Franklin and Maxwell's electrodynamics. And much of this knowledge was produced by one person -. J. Henry ... Most of his contemporaries could not be estimated as follows, and a small fraction of his enormous contribution to science. Now his research are among the great scientific discoveries. " The outstanding contribution of John. Henry in the study of electromagnetism considered opening them (almost simultaneously with Faraday) the phenomenon of electromagnetic induction. It is no accident it is called "American Faraday." ... Although thousands of people every fine day on the Mall in Washington Square linger in front of a monument to Joseph Henry established may seem implausible to the old building of the Smithsonian Institution ... but it's just the way that only a few of them firmly know who he is and what did he do.

"The discovery of electromagnetic induction Faraday Maclay" - article about how Michael Faraday made one of the most significant discoveries in electrical engineering. In the course of his experiments in 1830 by Joseph Henry for a year before Faraday discovered the phenomenon of electromagnetic induction! But if Faraday immediately printed the results of their experiments (London time was the scientific center of the world), then Henry's distant American heartland did not do it right away and therefore lost priority.