LECTUMS 



ON ASTRONOMY 



BY PROFESSOR A. CASWELL, OF BROWN UNIVERSITY. 



1 . The figure and magnitude of the earth. 



Every person who ventures to address a public assembly is supposed 

 to have something to present to them which is worthy of their atten- 

 tion, and which they can understand. In the treatment of scientific 

 subjects he must occupy himself mainly in giving information respect- 

 ing the facts and methods and laws of science. 



In appearing before you this evening I may be permitted, I trust, 

 ■without arrogance on my part or disparagement to you, to say that 

 my object is instruction. Any object lower than this would ill become 

 this place and the character of this noble Institution, which is doing 

 so much to stimulate investigation and develop the scientific resources 

 of our country. I wish to unfold to you the elementary methods by 

 which the astronomer advances step by step in investigation, until he 

 spans the heavens with his measuring rod and weighs the far oiF 

 planetary bodies as in a balance, and marks the point in the starry 

 concave where the flaming comet will disappear in the depths of ether, 

 and that other point with almost equal precision where it will reap- 

 pear after the flight of centuries. There are in astronomy refinements 

 of method, both practical and theoretical, which can be appreciated only 

 by rare gifts and profound study. But the elementary methods are 

 quite within the reach of ordinary minds. The law_, which it was dif- 

 ficult to discover, may be very easily understood and its results readily 

 traced. It might require a Newton or a La Place to unveil the me- 

 chanism ot the heavens, but when that is once done every beholder 

 may watch the wonderful evolutions. 



To accomplish the purposes I liave in view, I must first of all secure 

 your attention. For this I rely more upon the inherent interest and 

 grandeur of the subject than upon any adventitious attractions which 

 I may be able to throw around it. 



Astronomy has long claimed the pre-eminence of being the most 

 ancient and the most perfect of the sciences. And yet astronomy, in 

 some of its aspects, is a rapidly progressive and cumulative science. 



