to 1684 CASSINI discovered four more moons revolving about
_Saturn_. Since 1684 no new body had been added to the solar system.
It was thought complete for nearly a century.

In England, the remarkable discoveries of BRADLEY (1727-62) had been in
the field of practical astronomy, and his example had set the key-note
for further researches. France was just about beginning the brilliant
period of her discoveries in mathematical astronomy, and had no
observatory devoted to investigations like HERSCHEL'S, with the possible
exception of DARQUIER'S and FLAUGERGUES'. The observatories of SCHROETER
and VON HAHN, in Germany, were not yet active. The field which HERSCHEL
was created to fill was vacant, the whole world over. It was especially
so in England. The Royal Observatory at Greenwich, under MASKELYNE,
a skilful observer, whose work was mostly confined to meridian
observations, was no rival to a private observatory like HERSCHEL'S. The
private observatories themselves were but small affairs; those of the
king, at Kew, of Dr. WILSON, at Glasgow, of Mr. AUBERT, at Loampit Hill,
of the Count VON BRUHL, in London, being perhaps the most important.
The whole field was open. What was perhaps more remarkable, there was in
England, during HERSCHEL'S lifetime, no astronomer, public or private,
whose talents, even as an observer, lay in the same direction.

It hardly need be said that as a philosopher in his science, he had then
no rival, as he has had none since. His only associates even, were
MICHELL and WILSON.[15]

Without depreciating the abilities of the astronomers of England, his
cotemporaries, we may fairly say that HERSCHEL stood a great man among a
group of small ones.

Let us endeavor to appreciate the change effected in the state of
astronomy not only in England but in the whole world, simply by the
discovery of _Uranus_. Suppose, for example, that the last planet in our
system had been _Saturn_. No doubt HERSCHEL would have gone on. In spite
of one and another difficulty, he would have made his ten-foot, his
twenty-foot telescopes. His forty-foot would never have been built, and
the two satellites which he found with it might not have been
discovered. Certainly _Mimas_ would not have been. His researches on the
construction of the heavens would have been made; those were in his
brain, and must have been ultimated. The mass of observations of
_Saturn_, of _Jupiter_, of _Mars_, of _Venus_, would have been made and
pu