414 
ME. LOUIS VESSOT KING ON THE SCATTEEING AND 
Table IX. — Total Solar and Sky Eadiation Calculated at Washington Level from Mean Attenuation 
Coefficients. 
This table is drawn up on the same plan as Table VIE, making use of the Washington data given in 
Table II. The values of the “ apparent ” coefficients of attenuation, C, derived from the integrated solar 
radiation curves corresponding to different zenith distances of the sun are given below:— 
c- 
0°. 
0 
o 
0 
o 
0 
o 
0 
o 
O 
00 
Mean value C between 
0° and 60°. 
c 
•247 
•247 
•252 
•246 
•235 
•210 
o 
00 
1 
II 
lo 
1 
oo'' 
II 
iO 
The value of the apparent transmission of total radiation given for Washington* is e ^ = '787, 
C = • 240 in substantial agreement with the above mean value between 0° and 60°. 
The ratio 
E({)dA 
is approximately constant for all zenith distances to 70° and has the mean value '078. The value of this 
ratio for ( = 80° seems to indicate the existence of a rapidly increasing value of the ratio beyond that 
angle : the analysis by which sky radiation is calculated ceases to hold even approximately for greater 
zenith distances on account of the curvature of the earth. 
* ‘Annals,’ vol. II., p. 96. 
