ier belongs the credit of having been the real organizer of
the Paris Observatory. His work there was not dissimilar to that
of Airy at Greenwich; but he had a much more difficult task before
him, and was less fitted to grapple with it. When founded by Louis
XIV. the establishment was simply a place where astronomers of the
Academy of Sciences could go to make their observations. There was
no titular director, every man working on his own account and in
his own way. Cassini, an Italian by birth, was the best known of
the astronomers, and, in consequence, posterity has very generally
supposed he was the director. That he failed to secure that honor
was not from any want of astuteness. It is related that the monarch
once visited the observatory to see a newly discovered comet through
the telescope. He inquired in what direction the comet was going to
move. This was a question it was impossible to answer at the moment,
because both observations and computations would be necessary before
the orbit could be worked out. But Cassini reflected that the king
would not look at the comet again, and would very soon forget what
was told him; so he described its future path in the heavens quite
at random, with entire confidence that any deviation of the actual
motion from his prediction would never be noted by his royal patron.

One of the results of this lack of organization has been that the
Paris Observatory does not hold an historic rank correspondent to
the magnificence of the establishment. The go-as-you-please system
works no better in a national observatory than it would in a business
institution. Up to the end of the last century, the observations
made there were too irregular to be of any special importance.
To remedy this state of things, Arago was appointed director early in
the present century; but he was more eminent in experimental physics
than in astronomy, and had no great astronomical problem to solve.
The result was that while he did much to promote the reputation of
the observatory in the direction of physical investigation, he did
not organize any well-planned system of regular astronomical work.

When Leverrier succeeded Arago, in 1853, he had an extremely difficult
problem before him. By a custom extending through two centuries,
each astronomer was to a large extent the master of his own work.
Leverrier undertook to change all this in a twinkling, and, if reports
are true, without much regard to th