NO. 15 SMITHSONIAN EXPLORATIONS, I92I 3I 



established and continued at Mount Harqua Hala until January 20, 

 1921, when it was taken in charge by Mr. L. B. Aldrich. He remained 

 until May 20, 1921, when he was relieved by Mr. A. F. Moore, 

 formerly director of the Smithsonian private observing station at 

 Calama and Montezuma, Chile. Under Mr. Moore's charge, the 

 work has been continued steadily at Mount Harqua Hala, with the 

 assistance of ^Ir. F. A. Greeley. 



The Smithsonian Institution maintains from the income of the 

 Hodgkins fund a similar station at Mount Montezuma, near Calama, 

 Chile, under the direction of Mr. L. H. Abbot assisted by Mr. P. E. 

 Greeley. From this Chilean station daily telegrams are forwarded 

 to Buenos Aires, Argentina, giving the observed value of the solar 

 constant of radiation for the day. These data are employed regularly 

 by the Argentine Weather Bureau for weather-forecasting purposes. 



While the Smithsonian Institution is not yet in position to champion 

 the use of statistics of solar variation for meteorological forecasts, the 

 great interest which its studies of solar variability have aroused here 

 and abroad seems clearly to warrant the continued maintenance of 

 the Arizona and Chile solar stations under the best possible observ- 

 ing conditions for several years, until a satisfactory basis for a test 

 of the solar variability as a weather-forecasting element has been laid. 



The present year has unluckily proved unfortunate at both stations. 

 At Mount Harqua Hala the spring months were very hazy, the 

 summer and autumn months unusually cloudy, with almost unpre- 

 cedentedly heavy rainfall. At Montezuma the cloudiness of the 

 earlier months was quite unprecedented. During August and Sep- 

 tember a disarrangement of the apparatus caused apparently by earth- 

 quake, combined with illness of the director, led to the loss of manv 

 observing days. 



In October, Dr. Abbot began an inspection trip to Montezuma, 

 arriving at the station on November 15, and remaining until December 

 14. During this interval of 30 days, the observers fortunately were 

 able to determine the solar radiation on 26 days, and generally with 

 three or four closely agreeing determinations per dav. All of the 

 apparatus was readjusted and improved to the most perfect state of 

 fitness. Many of the results in these conditions proved of a higher 

 grade than ever before observed. In fact it would be hard to con- 

 ceive of anything which could add now to the excellence of the 

 Montezuma station and outfit. 



The accompanying illustrations show the desolate, rainless char- 

 acter of the region ; figure 31 shows the mountain top with the observ- 



