eans
have adopted the division of the week into seven days, and have named
them from the seven planets: now if we increase the number of the
planets this whole system falls to the ground."

To these arguments Galileo replied that whatever their force might be as
a reason for believing beforehand that no more than seven planets would
be discovered, they hardly seemed of sufficient weight to destroy the
new ones when actually seen. Writing to Kepler at this time, Galileo
ejaculates:

"Oh, my dear Kepler, how I wish that we could have one hearty laugh
together! Here, at Padua, is the principal professor of philosophy whom
I have repeatedly and urgently requested to look at the moon and planets
through my glass, which he pertinaciously refuses to do. Why are you not
here? What shouts of laughter we should have at this glorious folly! And
to hear the professor of philosophy at Pisa laboring before the Grand
Duke with logical arguments, as if with magical incantations, to charm
the new planets out of the sky."

A young German _protege_ of Kepler, Martin Horkey, was travelling in
Italy, and meeting Galileo at Bologna was favored with a view through
his telescope. But supposing that Kepler must necessarily be jealous of
such great discoveries, and thinking to please him, he writes: "I cannot
tell what to think about these observations. They are stupendous, they
are wonderful, but whether they are true or false I cannot tell." He
concludes, "I will never concede his four new planets to that Italian
from Padua, though I die for it." So he published a pamphlet asserting
that reflected rays and optical illusions were the sole cause of the
appearance, and that the only use of the imaginary planets was to
gratify Galileo's thirst for gold and notoriety.

When after this performance he paid a visit to his old instructor Kepler
he got a reception which astonished him. However, he pleaded so hard to
be forgiven that Kepler restored him to partial favor, on this
condition, that he was to look again at the satellites, and this time to
see them and own that they were there.

By degrees the enemies of Galileo were compelled to confess to the truth
of the discovery, and the next step was to outdo him. Scheiner counted
five, Rheiter nine, and others went as high as twelve. Some of these
were imaginary, some were fixed stars, and four satellites only are
known to this day.[30]

Here, close to the summit of his greatness, we must leave h