714 
the Legislature of Illinois. The growth of 
this infant city, then small even for an in- 
fant, into the great commercial metropolis 
of the West has been the just pride of its 
people and the wonder of the world. I 
mention it now because of a remarkable 
coincidence. With this civic growth has 
quietly gone on another, little noted by the 
great world, and yet in its way equally 
wonderful and equally gratifying to the 
pride of those who measure greatness by 
intellectual progress. If itbe true that “in 
nature nothing is great but man, in man 
nothing is great but mind,” then may knowl- 
edge of the universe be regarded as the true 
measure of progress. I, therefore, invite at- 
tention to the fact that American astronomy 
began with your city, and has slowly but 
surely kept pace with it until to-day our 
country stands second only to Germany in 
the number of researches being prosecuted, 
and second to none ia the number of men 
who have gained the highest recognition by 
their labors. 
In 1836 Professor Albert Hopkins, of 
Williams College, and Professor Elias 
Loomis, of Western Reserve College, Ohio, 
both commenced little observatories. Pro- 
fessor Loomis went to Europe for all his in- 
struments, but Hopkins was able even then 
to get some of his in this country. Shortly 
afterward a little wooden structure was 
erected by Captain Gilliss on Capitol Hill, 
at Washington, and supplied with a transit 
instrument for observing moon culmina- 
tions in conjunction with Captain 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 population of your city had increased 
to 703. 
The next decade, 1840 to 1850, was that 
in which our practical astronomy seriously 
SCIENCE. 
[N.S. Vout. VI. No. 150. 
commenced. The little observatory of 
Captain Gilliss was replaced by the Naval 
Observatory, erected at Washington during 
the years 1843-4 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 Bos- 
ton to erect the observatory of Harvard 
College. Thus it is little more than half a 
century since the two principal observa- 
tories in the United States were established. 
But we must not fora moment suppose that 
the mere erection of an observatory can 
mark an epoch in scientific history. What 
must have made the decade of which Ispeak 
ever memorable in American astronomy 
was not merely the erection of buildings, 
but the character of the work done by as- 
tronomers 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-discovered planet 
Neptune. He was the first astronomer to 
determine fairly good elements of the orbit 
of that planet, and, what is yet more re- 
markable, he was abie 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 deter- 
mination 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 applica- 
tion has not been fully written. In some 
‘points there seems to be as much obscurity 
as with the discovery of ether as an an- 
