ROWLAND, Henry Augustus III [1848-1901] -- American physicist

First professor of physics at Johns Hopkins (1875-1901); Invented the concave spectroscope diffraction grating; Proved similarity of effect of electric current and high speed electrostatic charge (1876); determined the thermo-mechanical equivalent of heat and the ohm (unit of electrical resistance); First president of American Physical Society (1899-1901).

ROWLAND, Henry Augustus, physicist, was born in Honesdale, Pa., Nov. 27, 1848; son of the Rev. Dr. Henry Augustus and Harriet (Heyer) Rowland; grandson of the Rev. Henry A. and Frances (Bliss) Rowland; great-grandson of the Rev. David Sherman and Mary (Spaulding) Rowland, and a descendant of Jonathan Edwards, and of the Rev. John Warham, first minister of Windsor, Conn. He was graduated at the Rensselaer Polytechnic institute at Troy, N.Y., C.E., 1870, and became a surveyor in western New York. He was instructor in physics at Rensselaer, 1872–74, and in 1874 was made assistant professor. He studied at Berlin in 1875, and in 1876 became professor of physics at Johns Hopkins university. He made many discoveries in electrical and solar science, and invented machines to aid him in his work. A plate of polished metal, ruled with close, parallel lines, possesses a refractory power very much beyond that of the prism commonly used, and the nearer these lines are to one another the greater the power of the plate. Professor Rowland invented a ruling engine capable of making 20,000 lines to the inch, the best achievement before that being the engine of Lewis M. Rutherfurd (q.v.), which ruled 17,000 lines to the inch. Professor Rowland was married June 4, 1890, to Henrietta, daughter of George Law and Helen (Davidge) Harrison, of Baltimore, Md. He invented in 1897 the multiplex printing telegraph, by means of which a telegram can be transmitted upon a typewriter and reproduced in typewritten format the receiving end; and he devised a means of making practical use of the force of Niagara for the generation of electricity. In 1899 he conducted a successful series of experiments to ascertain the cause of the magnetism of the earth, and determined to a nicety the value of an ohm, being a permanent member of the International commission for establishing electrical units. He received the honorary degrees, Ph.D. from Johns Hopkins in 1880, and LL.D. from Yale in 1883 and from Princeton in 1896; was made a chevalier of the Legion of Honor for his services at the Electrical congress at Paris in 1881, and in 1896 was advanced to the grade of officer, and later made a corresponding member of the British Association for the Advancement of Science. He was one of twelve foreigners to be admitted to membership in the Physical Society of London. He was elected to membership in the Natioanl Academy of Sciences in 1881, and in 1884 received for his researches in light and heat the Rumford medal from the American Academy of Arts and Sciences, of which he was an associate, and in 1897 the Matteucci medal. Me wrote many pamphlets and monographs, among which are: On Concave Gratings for Optical Purposes (1883); On the Relative Wave Lengths at the Lines of the Solar Spectrum (1886); On the Mechanical Equivalent of Heat (1880), and Photographs of the Normal Solar Spectrum. He died in Baltimore, Md., April 16, 1901, and in accordance with his expressed wish his ashes were deposited in the laboratory of Johns Hopkins university. [Twentieth Century Biographical Dictionary of Notable Americans]