14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



direction of the winds at particular localities. Such displacements of 

 the cyclones and anticyclones and wind directions so caused are prob- 

 ably the mechanisms involved in the large effects found in this paper. 



Addenda 



NOTE ON MR. CLAYTON'S INVESTIGATIONS OF THE RELATIONS 

 OF RADIATION AND TEMPERATURE^ 



By C. G. Abbot 



Nearly 40 years ago the late Secretary Langley, at that time Direc- 

 tor of the Allegheny Observatory, made the following remarkable 

 statement in his report of the Mount Whitney Expedition : 



"If the observation of the amount of heat the sun sends the earth 

 is among the most important and difficult in astronomical physics it 

 may also be termed the fundamental problem of meteorology, nearly 

 all whose phenomena would become predictable if we knew both the 

 original quantity and kind of this heat ; how it affects the constituents 

 of the atmosphere on its passage earthward ; how much of it reaches 

 the soil ; how through the aid of the atmosphere it maintains the 

 surface temperature of this planet, and how in diminished quantity 

 and altered kind it is finally returned to outer space." 



Let us set over against this pronouncement of Langley the final con- 

 clusion of Mr. Clayton in the paper which follows : " The results of 

 these researches have led me to believe: i. That if there were no 

 variation in solar radiation the atmospheric motions would establish a 

 stable system with exchanges of air between equator and pole and 

 between ocean and land, in which the only variations would be daily 

 and annual changes set in operation by the relative motions of the 

 earth and sun. 2. The existing abnormal changes, which we call 

 weather, have their origins chiefly, if not entirely, in the variations of 

 solar radiation." 



His whole paper deserves careful attention, but in order to fix in 

 a striking manner in the reader's mind the strength of his case for a 

 real correlation between solar radiation and terrestrial temperature, 

 I would draw attention to tables i and 2 of Mr. Clayton's main paper 



^ Clayton, H. H., Variation in solar radiation and the weather. Smithsonian 

 Misc. Coll., vol. 71, no. 3, 1920. 



