AMERICAN 



JOURNAL OF SCIENCE AND ARTS. 



[THIRD SERIES.] 



Art. VIII.— Astronomic, d Ohsermtion* on the Atmosphere of the 

 Rod;/ Uou,vui»s. , • 4..-I h i to 11,000 feet, 



in Utah and Wyoming Territories and Colorado; by Heney 

 Deapeb, M.D., Professor of Analytical Chemistry and Physi- 

 ology in the University of New York. 



Anyone who observes with a large telescope soon becomes 

 aware of the great obstacle atmospheric undulation offers to the 

 pursuit of astronomy, particularly in the application of photog- 

 raphy and the spectroscope. During two years when I photo- 

 graphed the Moon on every moonlight night at my observatory* 

 there were only three occasions on which the air was still enough 

 to give good results, and even then there was unsteadiness. 

 Out of 1,500 lunar negatives only one or two were really fine 

 pictures. A letter which the late Mr. Bond wrote to me states 

 that in seventeen years he had never met with a perfectly fault- 

 less night at the Cambridge Observatory. 



Such facts naturally cause astronomers to consider whether 



led to the C< :l Smyth to 



the Peak of Teneriffe ai <l Air. L; - to M tn. 1 

 it would seem that the only complete solution is to ascend high 

 mountain ranges or isolated peaks, and leave as much as possible 

 of the air below the telescope. 



Having had occasion during the months of August and Sep- 

 tember, 1876, to go on a hunting trip with two distinguished 

 officers of the United States Army into the Rocky Mountains 



* Professor Henry Draper's Observatory is at Hastings-on-Hudson, near New 



