ASPECTS OF AMERICAN ASTRONOMY. 91 



Loomis, of Western Reserve College, Ohio, both comineuced little 

 observatories. Professor Loomis weut to Europe for all his iustruments, 

 but Hopkins was able even then to get some of his in this country. 

 Shortly afterwards a little wooden structure was erected by Captain 

 Gilliss on Capitol Hill, at Washington, and supplied with a transit 

 instrument for observing moon culminations, in conjunction with Cap- 

 tain Wilkes, who was then setting out on his exploring expedition to 

 the Southern Hemisphere, The date of these observatories was prac- 

 tically the same as that on which a charter for the city of Chicago was 

 obtained from the legislature. With their establishment the popula- 

 tion of your city had increased to 703. 



The next decade, 1840 to 1850, was that in which our practical 

 astronomy seriously commenced. The little observatory of Captain 

 Gilliss was replaced by the Naval Observatory, erected at Washington 

 during the years 1843-44 and fitted out with what were then the most 

 approved instruments. About the same time the appearance of the 

 great comet of 1843 led the citizens of Boston to erect the observatory 

 of Harvard College. Thus it is little more than a half century since 

 the two principal observatories in the United States were established. 

 But we must not for a moment suppose that the mere erection of an 

 observatory can mark an epoch in scientific history. What must make 

 the decade of which I speak ever memorable in American astronomy 

 was not merely the erection of buildings, but the character of the work 

 done by astronomers away from them as well as in them. 



The Naval Observatory very soon became famous by two remarkable 

 steps which raised our country to an important position among those 

 applying modern science to practical uses. One of these consisted of 

 the researches of Sears Cook Walker on the motion of the newly dis- 

 covered planet Neptune. He was the first astronomer to determine 

 fairly good elements of the orbit of that planet, and, what is yet more 

 remarkable, he was able to trace back the movement of the planet in 

 the heavens for half a century and to show that it had been observed 

 as a fixed star by Lalande in 1795, without the observer having" any 

 suspicion of the true character of the object. 



The other work to which I refer was the application to astronomy 

 and to the determination of longitudes of the chronographic method 

 of registering transits of stars or other phenomena requiring an exact 

 record of the instant of their occurrence. It is to be regretted that 

 the history of this application has not been fully written. In some 

 points there seems to be as much obscurity as with the discovery of 

 ether as an antesthetic, which took place about the same time. Hap- 

 pily no such contest has been fought over the astronomical as over the 

 surgical discovery, the fact being that all who were engaged in the 

 application of the new method were more anxious to perfect it than 

 they were to get credit for themselves. We know that Saxton, of the 

 Coast Survey; Mitchell and Locke, of Cincinnati ; Bond, at Cambridge, 



