as
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 commenced. The little observatory of Captain
Gilliss was replaced by the Naval, then called the National
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 National Observatory 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 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 anaesthetic, which took place about the same time. Happily,
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;