A propos de cet article
First Edition of 'the vade-mecum of astronomers and physicists.' 391 pp. Buckram. Ex-University of Chicago and Yerkes Observatory Library. Bookplate and institutional ink stamp on front pastedown, stamp and pouch on rear pastedown. Ink stamp on title page and following leaf. A few pencil markings and a few in old ink. Else Very Good. '[T]he work for which he is best known [is] the invention and ruling of the concave spectral grating. The range, resolving power, and accuracy of a grating were determined respectively by the number, density, and regularity of its rulings. Lewis Rutherfurd, an amateur astronomer in New York City, had managed to rule up to two square inches of metal with thirty thousand lines per linear inch, but his gratings were inaccurate. Rowland recognized that to make a grating of highly uniform line-spacings, one needed an exceedingly regular drive screw in the ruling engine. He found that he could manufacture a nearly perfect drive screw from a roughly cut screw simply by grinding it in an eleven-inch-long nut which, split parallel to its axis, was clamped over the screw. With the problem of the screw overcome, Rowland could rule up to forty-three thousand lines per inch on more than twenty-five square inches of metal and, hence, construct gratings of unprecedented accuracy and resolving power. Rowland saw numerous advantages in ruling his gratings on a spherically concave grating rather than on a flat surface. Since such gratings were self-focusing, they eliminated the need for lenses, in which the glass absorbed infrared and ultraviolet radiation. More important, the optical properties of a concave grating permitted a vast simplification in the observation of spectra. . . . The concave grating reduced the work of days to a few hours, and Rowland sold over 100 of them at cost to physicists throughout the world. In the 1880's Rowland remapped the solar spectrum; his wavelength tables, which were ten times more accurate than their best predecessors, became the standard for over a generation. At the Paris Exposition of 1890 his gratings and map of the solar spectrum received a gold medal and a grand prize' (Daniel J. Kevles in D.S.B. XI: 578-9). 'In 1893 Rowland published 'A New Table of Standard Wave-Lengths' containing several hundred lines in the solar spectrum. This represented the results of some ten or more years of investigation, during which period he constructed the ruling engine and produced the first concave grating. This table of wave-lengths so surpassed in accuracy all previous work that it received world-wide acceptance and was made the basis of his 'Preliminary Table of Solar Spectrum Wave-Lengths [offered here],' which for a generation has been the world's standard and the vade-mecum of astronomers and physicists' (Charles E. St. John, Mount Wilson Observatory, Carnegie Institution of Washington, Pasadena, 'Revision of Rowland's Preliminary Tables of Solar Spectrum Wave-Lengths', Proc Natl Acad Sci U S A. 1927 September; 13(9): 678 683).
N° de réf. du vendeur 16567
Contacter le vendeur
Signaler cet article
