420 
]\IR. LOUIS VESSOT KING ON THE SCATTERING AND 
Table Xll.—Avemije Intensifies of Skf Itadiatiun, Mount JMilson. 
Obsei’vations are given at Mount Wilson* for the average total intensity of sky radiation taken for 
different azimuths. The theoretical formula corresponding to average sky intensity is by (66), 
rT{<k,i)d\ = 
liv Jo Jo 
The term in square brackets denoted by 
1 + cos^ d' 
1 + cos^ 
In calculating ai'ercuje skyjsun for equal solid angles, the value of 
to [”t( 0, C)r/A||”E(0rfA 
is derived by interpolation from Diagram XL 
In order to compare the attenuation coefficients on the dates of the above sky observations, these values 
taken from the Mount Wilson observations! are compared in a table with the mean values employed in 
the calculation. It will be noticed that the absorption constants on August 18, 190.5, are in much better 
agreement with the mean values than those of September 8, 1906. The result is that as we should expect 
the sky observations on the former date agree more closely with the calculated values than those on the 
latter. 
= 1 - sin^ </). 
.1 COS'^ f - 1 
1 + cos^ t 
1 1 + cos-^ t) 
27r Jo 1 + cos^ C 
- dtp 
sec (/) T (0, Q (/A.. 
0 
* ‘Armais,’ vol. II., Table 32, p. 151. 
t ‘Annals,’ vol. II., pp. 96-97. 
