86 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1919. 



had arranged to receive daily telegraphic reports of the values ob- 

 tained at Calama, Chile. The director of the observatory at Calama, 

 Mr. Moore, had conceived a feeling that the sky conditions were not 

 as favorable as perhaps might be secured in other parts of South 

 America or elsewhere and feared that it was unwise for the Institu- 

 tion to continue to conduct the operations there. On all of these 

 accounts it seemed necessary for Dr. Abbot to go to South America 

 and deal with these several matters. 



In accordance with the sundry civil act, which failed of passage on 

 March 4, 1919, but was approved July 19, 1919, the following authori- 

 zation was secured : 



The unexpended balance of the appropriation " For observation of the total 

 eclipse of the sun of June 8, 1918, and so forth," is reappropriated and made 

 available for observation of the total eclipse of the sun of May 28, 1919, visible 

 in Bolivia. 



The two 11-foot focus 3-inch cameras employed by the Smithsonian 

 observers at Wadesboro, N. C, in 1900, and again by Mr. Aldrich in 

 1918, were equipped with a collapsible tube and other mechanism, 

 so that they could be speedily arranged with equatorial clock-driven 

 motion to photograph an eclipse in South America. Mr. Moore, at 

 Calama, was instructed to arrange to join Dr. Abbot with the pyranom- 

 eter employed there, so as to observe the degree of darkening of the 

 sky and sun as the eclipse progressed. Arrived at Calama, the appa- 

 ratus was repacked for use in the field, and Messrs. Moore and Abbot 

 proceeded to La Paz, Bolivia, where, owing to the kindness shown 

 by Mr. Babbage, of the railroad, arrangements were made to observe 

 close to the railroad station at El Alto, situated about 1,500 feet above 

 La Paz, at an altitude of about 14,000 feet above sea level. The day 

 of the eclipse. May 29, proved very favorable. The sky was entirely 

 cloudless in the neighborhood of the sun for several hours. Mr. 

 Moore had observed during the day before and during the night, and 

 continued his observations each minute throughout the totality and 

 the succeeding partial phase up until about two hours after sunrise. 

 Dr. Abbot had set up and adjusted the photographic telescope with 

 Mr. Moore's aid, and except for one defect it operated perfectly. 

 This was that since the eclipse took place so very early in the morn- 

 ing, only 20 minutes after sunrise, the rate of motion of the sun 

 above the horizon was not uniform with that which would occur in 

 the middle of the day, owing to refraction. The apparatus had only 

 been set up the day before, so that there was not time to work out 

 this matter to know exactly how to rate the clock at the moment of 

 eclipse. Preliminary observations of May 28 had indicated that the 

 clockwork ran a little too slow. During the day it was speeded up 

 a little, but on the day of the eclipse it proved to be a trifle too fast, 

 so that the moon appears to be elliptical rather than perfectly round, 



