14 



SMITHSONIAN ^MISCELLANEOUS COLLECTIONS VOL. 72 



checked by independent observations. The ]\Iount Wilson work- 

 yielded results on less than a third of the days, and might well be 

 affected by variations of atmospheric humidity incident to the site 

 so near the Pacific Ocean and the cities al)OUt Los Angeles. These 

 objections could not but be admitted by Dr. Abbot, and led him to 

 make a great effort to strengthen the observations of solar variation. 

 Mr. John A. Roebling, of New Jersey, had indicated a strong 

 interest in the work. In conference with Dr. Abbot in May, 1920, he 

 generouslv gave the sum of eleven thousand dollars for the purposes 



Fig. 15. — Montezuma solar observ- 

 ing station near Calama, Chile. 

 Dwelling house, shop and garage. 



Fig. 16. — Montezuma solar observ- 

 ing station. Entrance to spectrobo- 

 lometer tunnel. Also pyrheliometric 

 apparatus. 



first, of removing the station theretofore on the plateau near Calama, 

 Chile, to a nearby mountain high enough above the plain to avoid 

 dust and smoke; second, of removing the "solar constant" outfit 

 from Mt. Wilson to the best mountain site available in the United 

 States ; third, the balance for any other objects closely associated 

 with these investigations. 



Under the zealous and able management of Director A. F. Moore, 

 a new observing station was selected and prepared at a place called 

 Montezuma, about 8 miles south of Calama on a mountain rising 

 about 2,000 feet above the local level, and about 9,500 feet above sea 



