ÅNGSTRÖM, A.J. (ANDERS JONAS). - THE DISCOVERY OF HYDROGEN IN THE SUN.

Ueber die Fraunhofer'schen Linien im Sonnenspectrum. (Mitgetheilt vom Hrn. verf. aus d. Oefversigt af K. vet. Acad. Förhandl." 1861, No 8, nebst einem späteren Zusatz).

Leipzig, Johann Ambrosius Barth, 1862. Without wrappers as issued in "Annalen der Physik und Chemie. Hrsg. von J.C. Poggendorff", Vierte Reihe Bd. 27 (117), Stück Zwei, No. 10. The entire issue offered. Titlepage to vol. 27. Pp. 193-352 a. 1 engraved plate. Ångströms paper: pp. 290-302.

First appearance in German of Ångström's famous paper in which he announced the discovery of hydrogen in the atmosphere of the sun and in which he also confirmed the probable existence of of other elements there. The paper appeared in "Oefversigt af K. Vet. Acad. Förhandl." in 1861. The German paper here is expanded. At the same time it was translated into English and publishe as "On the Fraunhofer Lines Visible in the Solar Spectrum".

Ångström was one of the early formulators of the science of modern spectroscopy; he wrote extensively on terrestrial magnetism, the conduction of heat, and especially spectroscopy. He published a monumental map of the normal solar spectrum that expressed the length of light waves in units of one ten-millionth of a millimeter, a unit of length now known as the angstrom. He discovered that hydrogen is present in the sun's atmosphere, and he was the first to examine the spectrum of the aurora borealis.

Order-nr.: 44063