37o THE POPULAR SCIENCE MONTHLY. 



as occasion demanded. In such an observatory the student would 

 acquire every habit of nice adjustment, delicate manipulation, accu- 

 rate judgment, which would be acquired in the best astronomical ob- 

 servatory, and the field for the mathematical discussion of his results 

 is simply limitless. 



In another aspect, too, does the foundation of such observatories 

 hold out important promises. It must be remembered that many of 

 our physical constants rest unfortunately upon too uncertain a basis. 

 The velocity of electricity and the density of the earth are examples. 

 We have to look, then, to scientific men for the establishment of these 

 and other facts as they truly are, and besides, for the discovery of the 

 vast number of unknown physical laws, some of which we must be- 

 lieve are entirely within our reach, and but waiting continued effort 

 to declare themselves. The laws of terrestrial magnetism, the con- 

 nection of the aurora borealis with other appearances, and like sub- 

 jects, seem upon the point of being elucidated. It must be remem- 

 bered, too, that one astronomical observatory can do the routine work 

 for an entire country, and that, once done, it is done forever, and that 

 any repetition of it, however useful it may be to the person making it, 

 is yet of no original value in the world. But the vast number of un- 

 classified facts in the domain of physics, and the almost infinite variety 

 of its unknown laws, will supply ample work for many more physi- 

 cal observatories than could possibly be established. It seems deci- 

 dedly to the advantage of the student and of the college that each 

 should have the benefit of a well-appointed physical observatory, and 

 it is certain that the class of American gentlemen who found and sus- 

 tain departments of this kind in our colleges (and it is a very large 

 class, to our honor be it said), will find, in the establishment of such 

 an observatory as we have advocated, the pleasure which comes from 

 effort wisely made. They will see (as they have a most undoubted right 

 to expect to see) the immediate usefulness and benefit of their gift, and 

 can hardly fail to have aided in the discovery of some one of the many 

 laws of physics which lie so close to us, almost demanding discovery. 



The wisest plan for the foundation of such an observatory may be 

 found in the form of a letter in the Smithsonian Report for 1870, al- 

 ready referred to, and it is as an introduction to that letter that the 

 present paper may claim to have any value. 



