arther to annihilate such an imputation, than to put it by the
side of the following passage, extracted from a memoir by this
celebrated astronomer, published in the _Philosophical Transactions_,
for the year 1805: "The specific difference existing between planets and
asteroids appears now, by the addition of a third individual of the
latter species, to be more completely established, and that
circumstance, in my opinion, has added more to the _ornament_ of our
system than the discovery of a new planet could have done."

Although much has not resulted from Herschel's having occupied himself
with the physical constitution of Jupiter, astronomy is indebted to him
for several important results relative to the duration of that planet's
rotation. He also made numerous observations on the intensities and
comparative magnitudes of its satellites.

The compression of Saturn, the duration of its rotation, the physical
constitution of this planet and that of its ring, were, on the part of
Herschel, the object of numerous researches which have much contributed
to the progress of planetary astronomy. But on this subject two
important discoveries especially added new glory to the great
astronomer.

Of the five known satellites of Saturn at the close of the 17th century,
Huygens had discovered the fourth; Cassini the others.

The subject seemed to be exhausted, when news from Slough showed what a
mistake this was.

On the 28th of August, 1789, the great forty-foot telescope revealed to
Herschel a satellite still nearer to the ring than the other five
already observed. According to the principles of the nomenclature
previously adopted, the small body of the 28th August ought to have been
called the first satellite of Saturn, the numbers indicating the places
of the other five would then have been each increased by a unity. But
the fear of introducing confusion into science by these continual
changes of denomination, induced a preference for calling the new
satellite the sixth.

Thanks to the prodigious powers of the forty-foot telescope, a last
satellite, the seventh, showed itself on the 17th of September, 1789,
between the sixth and the ring.

This seventh satellite is extremely faint. Herschel, however, succeeding
in seeing it whenever circumstances were very favourable, even by the
aid of the twenty-foot telescope.

The discovery of the planet Uranus, the detection of its satellites,
will always occupy one of the highest