72 THE POPULAR SCIENCE MONTHLY. 



THE SHERMAN ASTRONOMICAL EXPEDITION. 



Br EMMA M. CONVERSE. 



SCIENTIFIC observers have long seen the importance of securing 

 a position elevated above the fogs and impurities of the atmos- 

 phere at the sea-level, for the purpose of making more accurate astro- 

 nomical and meteorological observations. Accordingly, Prof. Peirce, 

 the Superintendent of the Coast Survey, petitioned Congress for means 

 to carry out such an undertaking. Congress made an appropriation 

 of $2,000 for this special object, independent of the geographical and 

 topograjmical constants of the station. 



Sherman, in Wyoming, situated on the highest point of the Union 

 Pacific Railway, and on the Rocky Mountain range, was agreed upon 

 as an eligible and convenient locality for the scene of operations ; and 

 the months of June, July, and August, 1872, were devoted to the work. 



The party consisted of General R. D. Cutts, an experienced officer 

 of the Coast Survey, who had charge of the expedition, Assistant Mos- 

 man, Aid Colonna, Prof. Young, Prof. Emerson, and Mr. Mead, of 

 Dartmouth College. There were also a photographer, a mechanician, 

 and two servants. The party had, as an escort, about a dozen soldiers 

 from Fort Russell, at Cheyenne, who assisted in keeping the hourly 

 series of meteorological observations, and were detailed to serve as a 

 protection from possible attacks of hostile Indians. 



It Was not until July that the members from Dartmouth College 

 were able to join the expedition. The trustees of the college had 

 loaned their valuable telescope for the occasion. It has an aperture 

 of 9 T 4 g- inches, and a focal length of 12 feet, with clock-work, and the 

 usual accompaniments, and is fitted with an automatic spectroscope, 

 having a dispersive power of 13 prisms. This telescope is one of the 

 best in the countiy in optical perfection, and in convenience and handi- 

 ness of mounting. 



The summit of a slight elevation was chosen as an eligible locality 

 for occupation. It was a short distance from the railroad-station, and 

 about 40 or 50 feet above the track. Three shanties of rough boards 

 were erected as observatories, one for the transit instrument, one for 

 the meteorological apparatus, and one for the equatorial telescope. 

 The altitude of the observatory is 8,300 feet above the level of the 

 sea, the latitude a little more than 44, and the longitude about 28 

 west from Washington. 



It was thought that Sherman combined unusual facilities for ac- 

 complishing the desired object of the expedition, which was to test the 

 advantages of a great elevation upon astronomic, and especially spec- 

 troscopic, work. The currents, impurities, and reflective power of the 

 atmosphere at the sea-level, interfere greatly with studies of this kind, 



