8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



Adopted constants of silver-disk pyrhcliometers 

 Smithsonian pyrheliometry , scale of 1913 



Instru- Present 



ment constant Location and remarks 



S.I. 1 0.3733 U. S. Weather Bureau, 1910. Modernized, 1929. 



S.I. 2 0.3743 Observatorie Physique Central Nicolas, St. Peters- 



burg, Russia, 1910 (loan) ; National Observatory, 

 Rio de Janeiro, Brazil, 1912. 



S.I. 3 0.3625 Conservatoire des Arts et Metiers, Paris, France, 1911. 



S.I. 4 0.3713 Royal University of Naples, Italy, 1911. Destroyed in 



World War II. 



S.I. 5 0.3715 U. S. Department of Agriculture, Physical Laboratory, 



1910. Modernized, 1931. On loan to Astrophysical 

 Observatory since 1926. 



S.I. 6 0.3666 Oficina Meteorologica, Buenos Aires, Argentina, 1911. 



S.I. 7 0.3638 Do. 



S.I. 8 0.3774 Central Observatory, Madrid, Spain, 1912. 



S.I. 9 0.3738 Imperial College of Science and Technology, London, 



England, 191 1. 



S.I. 10 0.3762 Koniglich Preussisches Meteorologisches Institut, Ber- 



lin, Germany, 191 1. 



S.I. II 0.3769 Meteorological Observatory, TenerifFe, Canary Is- 



lands, 1911. 



S.I. 12 0.3631 Koniglich Preussisches Meteorologisches Institut, Ber- 



lin, Germany, 1912. 



S.I. 13 0.3617 Schweizerische Meteorologische Centralanstalt, Zu- 



rich, Switzerland, 1912. 



S.I. 14 0.3721 University of Toronto, Toronto, Canada, 1912. Mod- 



ernized, 1937. 



S.I. 15 0.3609 National Bureau of Standards, Washington, D. C, 



1912. 



S.I. 16 0.3634 University of Arizona, Tucson, Ariz., 1912. Modern- 



ized, 1929. Sent to Service Botanique, Tunis, 1932. 



S.I. 17 0.3629 Harvard College Observatory Station, Arequipa, Peru, 



19 1 2. Sent to Smithsonian Observing Station, 

 Calama, Chile, 1919. Modernized, 1929. 



S.I. 18 0.3774 Observatorio Nacional, Rio de Janeiro, Brazil, 1913. 



S.I. 19 0.3737 Aeronautisches Observatorium, Lindenberg, Germany, 



1913- 



S.I. 20 0.3657 Italian Indo-Asiatic Expedition, 1913. Returned to 



Washington, 1916. Repaired, 1919. Sent to Observ- 

 tory, Helwan, Egypt, 1920. 



S.I. 21 0.371 1 Aeronautisches Observatorium, Lindenberg, Germany, 



1913- 



S.I. 22 0.3778 Observatorio Astronomico Nacional, Tacubaya, Mex- 



ico, 1913. 



S.I. 23 0.3683 Landwirtschaftliches Institut, Moscow, Russia, 1914. 



S.I. 24 0.3713 Meteorological Observatory, Teneriffe, Canary Islands, 



1914. 



S.I. 25 0.3717 Do. 



