INTO IAL SMITHSONIAN EXPEDITIONS, 1QIO-I9QII wi 
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 
a & 
Fic. 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 1912, 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- 
