no. 3 



RADIATION OF THE ATMOSPHERE ANGSTROM 



2 9 



lies in the possibility of measuring the radiation to the whole sky 

 and not only to a part of it, which is the case when one of the strips 

 must be shaded. It must always be regarded as a dangerous approxi- 



= III Ml 1 11 Inn 1 1 Hi III lllll I HUM/ 



F A B E 



Fig. 2. — The Pyrgeometer. 



mation to compute the radiation to the whole sky from the radiation 

 to a fraction of it, assuming a certain standard distribution of radia- 

 tion to the different zones of the sky. The method of adding up 



