8 REPORT OF THE SECRETARY. 



pounds. These investigations are now completed, and liave resulted 

 in a substantial contribution to this branch of science. 



Astro-phy steal Observatory. — The Smithsonian Astro-physical Ob- 

 servatory still occupies the temporary wooden shelter upon the grounds 

 just south of the Smithsonian building, and the money given to the In- 

 stitution for the erection of a more permanent building is still held 

 while awaiting the action of Congress in providing a site. The ob- 

 servatory has received much of my i^ersonal attention during the year. 



In statements to Congress and elsewhere some brief official expla- 

 nation has been given of the object of this observatory, which, as it 

 has not been explicitly given in previous reports, I repeat here in the 

 most succinct manner before entering on any description of the special 

 work. 



The general object of astronomy, the oldest of the sciences, was, un- 

 til a very late period, to study the places and motions of the heavenly 

 bodies, with little special reference to the Avants of man in his daily 

 life, other than in the application of the study to the purposes of navi- 

 gation. 



Within the past generation, and almost coincidentally with the dis- 

 covery of the spectroscope, a new branch of astronomy has arisen, 

 which is sometimes called astro-physies, and whose purpose is distinctly 

 different from that of finding the places of the stars, or the moon, or the 

 sun; which is the i)rincipal end in view at such an observatory as that, 

 for instance, at Greenwich. 



The distinct object of astro-physics is, in the case of the sun, for ex- 

 ample, not to mark its exact place in the sky, but to lind out how it 

 affects the earth and the wants of man on it; how its heat is distributed, 

 and how it in fact affects not only the seasons and the farmer's crops, 

 but the whole system of living things on the earth, for it has lately 

 been proven that in a physical sense, it, and almost it alone, literally first 

 creates and then modifies them in almost every possible way. 



We have however arrived at a knowledge that it does so, without 

 yet knowing in most cases how it does so, and we are sure of the great 

 importance of this last acquisition, while still largely in ignorance how 

 to obtain it. We are, for example, sure that the latter knowledge 

 would form among other things a scientific basis for meteorology and 

 enable us to predict the years of good or bad harvests, so far as these 

 depend on natural causes, independent of man, and yet we are still 

 very far from being able to make such a prediction, and we cannot 

 do so till we have learned more by such studies as those in question. 



Knowledge of the nature of the certain, but still imperfectly un- 

 derstood dependence of teriestrial events on solar causes^ is, then, of 

 the greatest practical consequence, and it is with these large aims of 

 ultimate utility in view, as well as for the abstract interest of scien- 

 tific investigation, that the Government is asked to recognize such 

 researches as of national importance ; for it is to such a knowledge of 



