MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 4T 



2. The steadiness of the air, as tested by the absence of scintillation 

 of tlie stars, was usually inferior to the steadiness at Washington. 



o. A very few nights at the western stations were not only ex- 

 tremely transparent but very steady ; and thus superior to anything to 

 be experienced in the east. But, unfortunately, such nights were very 

 exceptional. The practical conclusion from all this was that there was 

 no reason to believe that the 26-inch telescope of the Naval Observatory 

 would do better service, on the whole, in this region of the Rocky 

 Mountains than at Washington. This conclusion was reported to Dr. 

 Henry Draper in 1874, and was tested b}^ liiin in his journeys to 

 Wyoming, Utah, and Colorado in 1876, and it was entirely confirmed 

 by his independent observations in various parts of the Rocky Moun- 

 tain region. It has since been confirmed by parties from the Harvard 

 College Observatory (1887), also, for certain selected stations. 



Professor Campbell, now of the Lick Observatory, left the observa- 

 tory of Ann Arbor to loecome head of the Department of Mathematics 

 in the Universit}' of Colorado, at Boulder (5,500 feet), where he spent 

 several years. His report is that the sky is of great purity, but that 

 the stars are extremely unsteady; thus adding one more bit of expert 

 testimony and again confirming the general verdict as to the conditions 

 to be found in the Rocky Mountains generally. 



I have no doubt that the final verdict upon the Rocky Mountain 

 region in Montana, Wyoming, Colorado, and at least part of New Mex- 

 ico will be that it is not in general desirable to establish permanent 

 astronomical observatories on high mountains in these States. It is 

 possible that special stations may be found where special local condi- 

 tions may change this general conclusion. The States of California, 

 Arizona, and part of New Mexico will, probably, always be preferable 

 to the Rocky Mountain region proper, for mountain, astronomical, 

 oljservatories. 



Rocky Mountain Stations in Utah, Wyoming, and Colorado. 



In August and September, 1876, Dr. Henry Draper made a 

 journey in the Rocky Mountains and paid especial attention to the 

 conditions of the atmosphere for astronomical observations. He took 

 with him a small but very perfect achromatic telescope of 1^ inch aper- 

 ture and magnifying power of 60 diameters. Stations in the Wahsatch 

 Mountains of Utah and in the Rocky Mountains of Wyoming and 

 Colorado, from 4500 to 11,000 feet in elevation, were occupied. Pro- 

 fessor Draper's general conclusions were : 



On the whole, the astronomical condition, particularly for photographic re- 

 searches, is unpromising. In only one place were steadiness and transparency 

 combined, and only two nights out of fifteen were exceptionally fine. The trans- 



