76 



MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



3. REDUCTloy OF OlSSERyATIOSS MADE WITH THE BLACK AND BRIGHT THERMOMETERS EXPOSED IN FULL 



SUNLIGHT, DVT NOT IX TACVO. 



The snme forimila used for tlie reduction of observatiou.s with Violle's bulbs .serves for the 



computation of .'-•olar intensities from readiug.s of bhick and bright bulb thermometers not in 



vacuo. The absorption constant a i.s, however, different. In the computation, the results of 



which are given in the following table, the value a = \ is adopted as representing the theoretical 



value of the radiating jjower of the bright bulb in terms of that of the black bulb : 



Computation of relative solar intensities. 



[Black and bright bulbs not in vacuo.] 

 APRIL 28. 



APRIL 30. 



MAY 1. 



