no. 3 



RADIATION OF THE ATMOSPHERE ANGSTROM 



67 



ordinates represent the radiation within a solid angle of 768.6 ° and 

 consequently ought to be divided by the same number. The total 

 radiation calculated in that way, is given in table IX, together with 

 the total radiation observed under the same conditions. The mean 



Zenith distance. 

 Fig. 12. — Radiation from horizontal surface to different parts of the sky. 



difference between the two values is only 0.003, y i z -> l ess ' than 2 per 

 cent. Considering the great difficulty of the observations upon which 

 the computed value is based, the agreement must be regarded as very 

 satisfactory. I therefore think we are justified in drawing there- 

 from the following conclusions : 



