Henry Augustus Rowland
Encyclopedia
Henry Augustus Rowland was a U.S. physicist
. Between 1899 and 1901 he served as the first president of the American Physical Society
. He is remembered today particularly for the high quality of the diffraction grating
s he made and for the work he did with them on the solar spectrum.
. From an early age he exhibited marked scientific tastes and spent all his spare time in electrical and chemical experiments. At the Rensselaer Polytechnic Institute
at Troy, N.Y. he graduated in 1870, and he then obtained an engagement on the Western New York railway. But the work there was not to his liking, and after a short time he gave it up for an instructorship in natural science at the University of Wooster, Ohio, which in turn he resigned in order to return to Troy as assistant professor of physics. Finally, in 1876, he became the first occupant of the chair of physics at the Johns Hopkins University
, Baltimore, a position which he retained until his premature death on the April 16, 1901.
Rowland was one of the most brilliant American scientists of his day, and it is curious that at first his merits were not perceived in his own country. He was unable to secure the publication of many of his early scientific papers; but James Clerk Maxwell
at once saw their excellence, and had them printed in the Philosophical Magazine. When the managers of the Johns Hopkins University asked advice in Europe as to whom they should make their professor of physics, he was pointed out in all quarters as the best man for the post. In the interval between his election and the assumption of his duties at Baltimore, he studied physics under Helmholtz at Berlin, and carried out a well-known research on the effect of an electrically charged body in motion, showing it to give rise to a magnetic field. As soon as he was settled at Baltimore, two important pieces of work engaged his attention. One was a redetermination of the ohm
. For this he obtained a value which was substantially different from that ascertained by the committee of the British Association appointed for the purpose, but ultimately he had the satisfaction of seeing his own result accepted as the more correct of the two. The other was a new determination of the mechanical equivalent of heat. In this he used Joule's paddle-wheel method, though with many improvements, the whole apparatus being on a larger scale and the experiments being conducted over a wider range of temperature. He obtained a result distinctly higher than Joule's final figure; and in addition he made many valuable observations on the thermodynamics involved, and on the variation of the specific heat of water, which J. P. Joule had assumed to be the same at all temperatures. In 1882, before the Physical Society of London, he gave a description of the diffraction grating
s, with which his name is specially associated, and which have been of enormous advantage to astronomical spectroscopy. These gratings consist of pieces of metal or glass ruled by means of a diamond point with a very large number of parallel lines, on the extreme accuracy of which their efficiency depends. For their production, therefore, dividing engines of extraordinary trueness and delicacy were required, and in the construction of such machines Rowland's engineering skill brought him conspicuous success. The results of his labors may be found in the elaborate Photographic Map of the Normal Solar Spectrum (1888) and the Table of Solar Wave-Lengths (1898). In the later years of his life he was engaged in developing a system of multiplex telegraphy
.
He authored A Plea for Pure Science, in 1883 an important document for the understanding of the relationship between science in university and in commercial contexts in the late nineteenth and early twentieth century.
The National Academy of Sciences
awarded Rowland the Henry Draper Medal
in 1890 for his contributions to astrophysics
. He won the Matteucci Medal
in 1895.
in Baltimore was designated a U.S. National Historic Landmark
.
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
. Between 1899 and 1901 he served as the first president of the American Physical Society
American Physical Society
The American Physical Society is the world's second largest organization of physicists, behind the Deutsche Physikalische Gesellschaft. The Society publishes more than a dozen scientific journals, including the world renowned Physical Review and Physical Review Letters, and organizes more than 20...
. He is remembered today particularly for the high quality of the diffraction grating
Diffraction grating
In optics, a diffraction grating is an optical component with a periodic structure, which splits and diffracts light into several beams travelling in different directions. The directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as...
s he made and for the work he did with them on the solar spectrum.
Life and work
Rowland was born in Honesdale, PennsylvaniaHonesdale, Pennsylvania
Honesdale is a borough in and the county seat of Wayne County, Pennsylvania, United States. It is located northeast of Scranton. The population was 4,874 at the 2000 census....
. From an early age he exhibited marked scientific tastes and spent all his spare time in electrical and chemical experiments. At the Rensselaer Polytechnic Institute
Rensselaer Polytechnic Institute
Stephen Van Rensselaer established the Rensselaer School on November 5, 1824 with a letter to the Rev. Dr. Samuel Blatchford, in which van Rensselaer asked Blatchford to serve as the first president. Within the letter he set down several orders of business. He appointed Amos Eaton as the school's...
at Troy, N.Y. he graduated in 1870, and he then obtained an engagement on the Western New York railway. But the work there was not to his liking, and after a short time he gave it up for an instructorship in natural science at the University of Wooster, Ohio, which in turn he resigned in order to return to Troy as assistant professor of physics. Finally, in 1876, he became the first occupant of the chair of physics at the Johns Hopkins University
Johns Hopkins University
The Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...
, Baltimore, a position which he retained until his premature death on the April 16, 1901.
Rowland was one of the most brilliant American scientists of his day, and it is curious that at first his merits were not perceived in his own country. He was unable to secure the publication of many of his early scientific papers; but James Clerk Maxwell
James Clerk Maxwell
James Clerk Maxwell of Glenlair was a Scottish physicist and mathematician. His most prominent achievement was formulating classical electromagnetic theory. This united all previously unrelated observations, experiments and equations of electricity, magnetism and optics into a consistent theory...
at once saw their excellence, and had them printed in the Philosophical Magazine. When the managers of the Johns Hopkins University asked advice in Europe as to whom they should make their professor of physics, he was pointed out in all quarters as the best man for the post. In the interval between his election and the assumption of his duties at Baltimore, he studied physics under Helmholtz at Berlin, and carried out a well-known research on the effect of an electrically charged body in motion, showing it to give rise to a magnetic field. As soon as he was settled at Baltimore, two important pieces of work engaged his attention. One was a redetermination of the ohm
Ohm
The ohm is the SI unit of electrical resistance, named after German physicist Georg Simon Ohm.- Definition :The ohm is defined as a resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere,...
. For this he obtained a value which was substantially different from that ascertained by the committee of the British Association appointed for the purpose, but ultimately he had the satisfaction of seeing his own result accepted as the more correct of the two. The other was a new determination of the mechanical equivalent of heat. In this he used Joule's paddle-wheel method, though with many improvements, the whole apparatus being on a larger scale and the experiments being conducted over a wider range of temperature. He obtained a result distinctly higher than Joule's final figure; and in addition he made many valuable observations on the thermodynamics involved, and on the variation of the specific heat of water, which J. P. Joule had assumed to be the same at all temperatures. In 1882, before the Physical Society of London, he gave a description of the diffraction grating
Diffraction grating
In optics, a diffraction grating is an optical component with a periodic structure, which splits and diffracts light into several beams travelling in different directions. The directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as...
s, with which his name is specially associated, and which have been of enormous advantage to astronomical spectroscopy. These gratings consist of pieces of metal or glass ruled by means of a diamond point with a very large number of parallel lines, on the extreme accuracy of which their efficiency depends. For their production, therefore, dividing engines of extraordinary trueness and delicacy were required, and in the construction of such machines Rowland's engineering skill brought him conspicuous success. The results of his labors may be found in the elaborate Photographic Map of the Normal Solar Spectrum (1888) and the Table of Solar Wave-Lengths (1898). In the later years of his life he was engaged in developing a system of multiplex telegraphy
Telegraphy
Telegraphy is the long-distance transmission of messages via some form of signalling technology. Telegraphy requires messages to be converted to a code which is known to both sender and receiver...
.
He authored A Plea for Pure Science, in 1883 an important document for the understanding of the relationship between science in university and in commercial contexts in the late nineteenth and early twentieth century.
The National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
awarded Rowland the Henry Draper Medal
Henry Draper Medal
The Henry Draper Medal is awarded by the United States National Academy of Sciences "for investigations in astronomical physics". Named after Henry Draper, the medal is awarded with a gift of USD $15,000...
in 1890 for his contributions to astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
. He won the Matteucci Medal
Matteucci Medal
The Matteucci Medal was established to award physicists for their fundamental contributions. Under an Italian Royal Decree dated July 10, 1870, the Italian Society of Sciences was authorized to receive a donation from Carlo Matteucci for the establishment of the Prize.Matteucci Medalists* 1868...
in 1895.
Commemoration
The Henry August Rowland HouseHenry August Rowland House
Henry August Rowland House is a site significant for its association with Henry Augustus Rowland, a physicist.The house at 917 Cathedral Street in Baltimore, Maryland was declared a National Historic Landmark in 1975....
in Baltimore was designated a U.S. National Historic Landmark
National Historic Landmark
A National Historic Landmark is a building, site, structure, object, or district, that is officially recognized by the United States government for its historical significance...
.
External links
- American Institute of Physics page on Rowland's work and published papers
- Astrophysical Journal, 1901, vol. 13, p.241
- Monthly Notices of the Royal Astronomical Society, 1902 p.245
- The Physical Papers of Henry Augustus Rowland (Baltimore : Johns Hopkins Press, 1902) (digitized by Internet ArchiveInternet ArchiveThe Internet Archive is a non-profit digital library with the stated mission of "universal access to all knowledge". It offers permanent storage and access to collections of digitized materials, including websites, music, moving images, and nearly 3 million public domain books. The Internet Archive...
)