moon
revolves round our own globe, he drew up an account of his discovery, in
which he gave to the four new bodies the names of the _Medicean Stars_,
in honour of his patron, Cosmo de Medici, Grand Duke of Tuscany. This
work, under the title of "Nuncius Sidereus," or the "Sidereal
Messenger," was dedicated to the same prince; and the dedication bears
the date of the 24th of March, only two days after he concluded his
observations.

The importance of this great discovery was instantly felt by the enemies
as well as by the friends of the Copernican system. The planets had
hitherto been distinguished from the fixed stars only by their relative
change of place, but the telescope proved them to be bodies so near to
our own globe as to exhibit well-defined discs, while the fixed stars
retained, even when magnified, the minuteness of remote and lucid
points. The system of Jupiter, illuminated by four moons performing
their revolutions in different and regular periods, exhibited to the
proud reason of man the comparative insignificance of the globe he
inhabits, and proclaimed in impressive language that that globe was not
the centre of the universe.

The reception which these discoveries met with from Kepler is highly
interesting, and characteristic of the genius of that great man. He was
one day sitting idle, and thinking of Galileo, when his friend
Wachenfels stopped his carriage at his door, to communicate to him the
intelligence. "Such a fit of wonder," says he, "seized me at a report
which seemed to be so very absurd, and I was thrown into such agitation
at seeing an old dispute between us decided in this way, that between
his joy, my colouring, and the laughter of both, confounded as we were
by such a novelty, we were hardly capable, he of speaking, or I of
listening. On our parting, I immediately began to think how there could
be any addition to the number of the planets without overturning my
'Cosmographic Mystery,' according to which Euclid's five regular solids
do not allow more than six planets round the sun.... I am so far from
disbelieving the existence of the four circumjovial planets, that I long
for a telescope, to anticipate you, if possible, in discovering _two_
round Mars, as the proportion seems to require, _six_ or _eight_ round
Saturn, and perhaps _one_ each round Mercury and Venus."

In a very different spirit did the Aristotelians receive the "Sidereal
Messenger" of Galileo. The principal professor o