NO. 3 SMrniS(JNlAN KXri.ORAllONS, 1915 I [f) 



The need is very uri^ent that other ohservins^' stations in remote 

 rejL^ions of the earth take np the daily measurement of solar radiation 

 in e()()]>eration with the Ast roplivsii-al ( )l)servatory. I'leferahly not 

 less than four stations in relatively cloudless rej^ions, widely sep- 

 arated, should he enyai^ed in this work. The variation of the sun 

 is estahlished. Its inlluence on terrestrial climate and t-onditions 

 of growth of vci^etation cannot he well determined unless the residts 

 of the .Astrophysical ( )l)servatory are verified and supplemented 

 hy prolonged routine ohservin;^ at several cooperalini; stations. 



