﻿NO. II 



SMITHSONIAN EXPEDITIONS, I9IO-I9I 



The station at Washington is unsuitable for this purpose because 

 clouds so often interfere. A station near the city of Mexico was 

 proposed and would have been occupied in July, but just as definite 

 arrangements were being concluded the town where the expedition 

 was to locate was reported sacked by a war party. As the conditions in 

 Mexico seemed likely to remain disturbed for some time, another 

 part of the world was chosen. Considerations of accessibility, favor- 

 able climate, high altitude, and peaceful conditions, seemed to recom- 

 mend Algeria. 



Such of the Algerian observations as have been thus far completely 



Fig. 4. — Arab judge. Photograph by Abbot. 



reduced seem to be very promising and indicate that the expeditionary 

 measurements were equally as definitive as those made at the per- 

 manent station on Mount Wilson. Great confidence is felt, that, as 

 a result of the present expedition, supplemented if necessary by the 

 continuation of it in 19 1.2, a satisfactory conclusion will be reached 

 as to the supposed variability of the sun. 



Returning, Mr. Abbot visited Naples, Potsdam, London, and Paris, 

 for the purpose of comparing the silver disk pyrheliometers furnished 

 by the Institution to observers in those cities, with a similar instrument 

 used by the expedition in Algeria. Comparisons were made satis- 



