Henry Augustus Rowland

Henry Augustus Rowland

Henry Augustus Rowland (* 27. November 1848 in Honesdale, Pennsylvania, † 16. April 1901 in Baltimore, Maryland) was an US-American physicist. He worked mainly in the area of electromagnetism. Admits became it by the concave diffraction gratings manufactured by him, by the z. B. sunning spectrum more exactly than up to then admits to be determined could.

Rowland came of to a family with a set of Protestant theologians. It was intended for religious career. Rowland was interested however already as a pupil in physics and accomplished frequently experiments in the parental house, in order to acquire itself physical basic knowledge. Since it revolted against the career planned for it, it was finally sent at the age from seventeen years on the Rensselaer Technological of institutes. it graduated to 1870 there to engineer. After he had worked afterwards two years long at a course company and as a teacher in Wooster (Ohio), he returned to Rensselaer, in order to teach natural history.

Whenever it permitted its time, it accomplished research in the area of the magnetism. Since the American journal OF Science rejected a publication of its results, he turned to James Maxwell in Great Britain. Maxwell was impressed and a publication compelled in the Londoner Philosophical of magazines, which received little attention in the states however.

Rowland showed up increasingly indignant about the situation in its Institut and the inadequacies of the research possibilities in the USA generally. The university enterprise is coined/shaped of mediocrity, the professors would regard research as waste of time.

1875 it finally met with Daniel Coit Gilman, which developed a faculty to again created John Hopkins university. This university was developed the first real research establishment in the states, after German model. Rowland was sent on a journey to Europe, in order to regard laboratories and buy Gerätschaften.

At the citizen of Berlin Helmholtz - Institut accomplished it a fundamental experiment, since the necessary means were to it for the first time here at the disposal. It concerned magnetic effects with a rotary, electrically charged metal disk. The experiment was extremely difficult, required extensive computations, whereby the measured effects were because of the detection limit. Rowland succeeded finally the proof that a rotary, electrically charged body produce a magnetic field. This discovery received large attention in the professional world.

Rowland returned with a selection of the best Gerätschaften to John the Hopkins university. It spent however as little time as possible on the teachings and administrative tasks, but experimented in its laboratory. With its students and its colleagues he was every now and then feared, since he would not tolerate and in his criticism be hurting could mediocrity.

Although Rowland was a capable mathematician and provided some work over the theory of electromagnetism, its largest abilities lay in practical experimenting. It determined the absolute value of the electrical resistance, the relationship of electrical units, the mechanical equivalent of the warmth as well as the change of the specific thermal capacity of water at different temperatures. It energized a set of experiments, which finally led to the discovery of the hall effect by one of its graduate students.

When its largest contribution applies to the science an improved diffraction grating, with whose development it began 1882. With the fact he discovered that a lattice applied on a concave surface supplied the best results. Rowlands diffraction gratings, which were ten times more exact than past devices, were supplied to all world and formed the basis for spectroscopic applications in physics, chemistry and astronomy. Rowland used its lattices around the spectrum of the sun to study in detail. In the year 1887 it published an Atlas with the complete solar spectrum and thousands absorption lines, that became for the next years the standard work.

For its achievements Rowland became numerous honours assign. Thus it received the universities of John Hopkins (1880), Yale (1883) and Princeton (1896) and in France the knight of the Ehrenlegion was appointed. It was one of twelve foreigners, who were accepted to the Londoner Physical Society. 1881 it was accepted to national the Academy OF Sciences.

As delegates of the US Government it participated in international congresses for the definition of electrical units.

To 4. June 1890 he married Henrietta Law. It experienced short time later that it was gotten sick to it only few Lebensjahre with Diabetis and remains. In order to secure the financial situation its family, he dedicated in the future improvements in the area of the Telegrafie and announced themselves several inventions to the patent . Since it wanted to leave something durable to physics, he became joint founder and first president of the American Physical Society.

1901 it died in Baltimore. Its ash was let in, its desire accordingly, into a wall of its laboratory.

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