NO. 14 ABBOT SILVER-DISK PYRHELIOMETER ALDRICH II 



Various A.P.O. instruments 



Instrument Constant Location and remarks 



A.P.O. IV 0.5118 Copper disk. 1906. Mount Wilson, Calif. 



A.P.O. VII 0.5072 Copper disk. 1906. Alount Wilson, Calif. 



A.P.O. VIII 0.5150 Copper disk. 1906. U. S. Weather Bureau and 



Mount Wilson. 



A.P.O. 8 0.3760 First silver-disk instrument. 1909. Washing- 



ton and Mount Wilson. Repaired 1910 and 

 called A.P.O. 8b. s. 



A.P.O. 8bi 0.3786 Modernized 1927. Reserved at Washington for 



comparisons only. 



A.P.O. 9 0.3631 Built 1910. Used at Washington, Mount Wilson, 



Mount Whitney, Algeria, Arizona. Modern- 

 ized 1928 and called A.P.O. 9bi8. 



A.P.O. 9bi» 0.3684 Zentralanstalt fiir Meteorologie und Geodyna- 



mik, Vienna, Austria, 1928. 



A.P.O. 10 0.3720 Built 1923. Sent to Harqua Hala and Table 



Mountain. 



A.P.O. II 0.367s Sent to Mount Brukkaros, Southwest Africa, 



1925. Modernized and sent to Mount St. 

 Katherine, Egypt, 1933. Repaired 1938 and 

 sent to Tyrone, N. Mex., Miami, Fla., and 

 Table Mountain, Calif. 



A.P.O. 12 0.3618 Table Mountain, Calif., 1928. 



A.P.O. 13 0.3893 Mount St. Katherine, Egypt, 1932. Rebuilt 1938 



and sent to Tyrone, N. Mex., Miami, Fla., and 

 Table Mountain, Calif. 



A.P.O. 14 0.3854 Mount St. Katherine, 1932; Tyrone, N. Mex., 



Miami, Fla., Table Mountain, Calif. 



