The Astrophysical Observatory 4 2 7 



Congress, a one-story building, or rather shed, whose object 

 was to furnish an immediate shelter for the instruments al- 

 ready ordered, and to enable some work to be done under 

 the appropriation while a more suitable site and building were 

 being provided. This site has not yet, after a lapse of over 

 six years, been obtained, and the investigations which are to 

 be described have been carried on under all the disadvantages 

 of such an entirely inadequate installation. 



It will be seen in the subsequent description of this work 

 that above any other department, even, of astronomical re- 

 search, it demands entire quiet and absence of tremor in the 

 surroundings, and that it has been necessary to give so long 

 a time to certain researches is due to the difficulties inherent 

 in the site rather than in the methods of observation. 



I MAY preface a brief account of the work of this new observ- 

 atory by repeating a portion of what has been already said, in 

 laying before the committees of appropriations of the Senate 

 and House, the reasons which should induce government aid : 



"The general object of astronomy, the oldest of the scien- 

 ces, was, until a very late period, to study the places and mo- 

 tions of the heavenly bodies, with little special reference to 

 the wants of man in his daily life, other than in the applica- 

 tion of the study to the purposes of navigation. 



"Within the past generation, and almost coincidentally 

 with the discovery of the spectroscope, a new branch of as- 

 tronomy has arisen, which is sometimes called astrophysics, 

 and whose purpose is distinctly different from that of finding 

 the places of the stars, or the moon, or the sun, which is the 

 principal end in view at such an observatory as that, for in- 

 stance, at Greenwich. 



" The distinct object of astrophysics is, in the case of the 

 sun, for example, not to mark its exact place in the sky, but 

 to find out how it affects the earth and the wants of man on 



