on the Atmosphere of the Rocky Mountains. 91 



night at my observatory. Capella, which was just clear of the 

 house-tops across the street, twinkled as badly both to the 

 naked eye and in the telescope as I have ever seen it at the sea- 

 level. Lieutenant Warren, of Camp Douglas (a military post 

 near the city) said there had been a heavy rain the week 

 previous and the air was more moist than usual. I had noticed 

 that the sun set among just such a bank of clouds as we are 

 accustomed to see in New York. I was somewhat prepared for 

 a tremulous condition in these high regions, because, the pre- 

 ceding niarht having stopped for a few minutes at Fort Steele, 

 on the Union Pacific Eailroad, I perceived that Antares 

 twinkled very much though we were nearly 7,000 feet above 

 the sea. 



However, in order to make a thorough trial it seemed best to 

 ascend one of the high peaks of the Wahsatch, and accordingly 

 the Red Butte was selected. The officers at Camp Douglas 

 I the trip in everv wav, furnishing horses and a guide, 

 and the surgeon of the Post; Dr. Smart, who is an able and 

 scientific man, accompanied me. The peak proved to be 7,350 

 feet high. Though it was quite clear when we started, clouds 

 gathered in every direction as the sun went down, and at night- 

 ... r ... gky was entirely overcast. Moreover, the wind blew so 

 strongly that it was necessary to retire over the brow of the 

 :. and eventually we returned to Camp Douglas. At 

 this point, 5,250 feet above the sea and about 600 feet higher 

 than S t Lake Citv, the telescope was set up to take advantage 

 of some breaks in the clouds, throng , i, h tl Moon. Antares, 

 <? Ursas Majoris and Jupiter appeared. With a power of only 

 twenty the twinkling was surprisingly great : I do not remember 

 ever to have seen it worse with mv large instruments. 



These results led to an examination into the meteorology of 

 Salt Lake Citv, so as to find out the rainfall and its di-- 

 and the percentage of cloudy days. Dr. Smart had the follow- 

 ing copy of the post records made for me : 



Table 1.— Rainfall and other Cloudy Days at Salt Lake City. 



