2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



Hence it is with unusual satisfaction that I am able to report the 

 close agreement between the results obtained at Mount St. Katherine, 

 our new station in Egypt, and those obtained on the same days at 

 Montezuma in Chile. For since these totally independent stations are 

 in opposite hemispheres, winter at the one coincides with summer at 

 the other. If the contrasting atmospheric and geometric conditions 

 of winter and summer do not bring about appreciable discordance, we 

 may, it would seem, now admit that Langley's two obstacles are sensi- 

 bly overcome, and the work which has gone on at Montezuma for 

 some years may be accepted with still greater confidence than 

 heretofore. 



In the year 193 1 I published, under the title " Weather Dominated 

 by Solar Changes ", evidence that the short-interval changes in the 

 intensity of the sun's radiation are of considerable influence in govern- 

 ing the ordinary fluctuations of weather. The solar-radiation values 

 used in that paper were exclusively from the Smithsonian station at 

 Montezuma, Chile. The results seemed to indicate that solar fluctua- 

 tions of less than 0.5 percent are associated with notable weather 

 changes. But it was impossible from the observations at one station, 

 subject to accidental errors of the instruments and observers and to 

 the difficulty of evaluating the losses in our atmosphere, to be sure 

 of distinguishing solar changes of less than 0.5 percent from errors 

 of observation, except when numerous apparently favorable cases 

 were averaged. 



Our station at Table Mountain, Calif., did not then and does not 

 now yield results as accurate as those of Montezuma. The difficulty 

 at Table Mountain lies not in the inadequacy of the apparatus or the 

 observers, but in some obscure invisible changes of atmospheric con- 

 ditions, whose efifects we have hitherto been unable to eliminate 

 completely. New efforts to improve Table Mountain results are now 

 on foot. 



With the generous support of the National Geographic Society, 

 an attempt was made about lO years ago to find and equip a support- 

 ing station in the Eastern Hemisphere equal to Montezuma. After 

 a journey to Algeria, Egypt, Baluchistan, and South Africa, I fixed 

 on Mount Brukkaros in South-West Africa as most suitable. Five 

 years of observing there demonstrated that owing to high winds, 

 which carry dust over the mountain, this station was inferior both to 

 Montezuma and to Table Mountain. 



Thereupon, with generous support from Mr. John A. Roebling, 

 Mr. and Mrs. A. F. Moore made a second journey of exploration 

 occupying about 20 months. They were equipped with portable in- 



