eo, "though of advanced age, mounted to the top
of one of the highest towers to watch the ships, which were visible
through my glass two hours before they were seen entering the harbour,
for it makes a thing fifty miles off as near and clear as if it were
only five." Among the people too the instrument excited the greatest
astonishment and interest, so that he was nearly mobbed. The Senate
hinted to him that a present of the instrument would not be
unacceptable, so Galileo took the hint and made another for them.

[Illustration: FIG. 39.--Portion of the lunar surface more highly
magnified, showing the shadows of a mountain range, deep pits, and other
details.]

They immediately doubled his salary at Padua, making it 1000 florins,
and confirmed him in the enjoyment of it for life.

He now eagerly began the construction of a larger and better instrument.
Grinding the lenses with his own hands with consummate skill, he
succeeded in making a telescope magnifying thirty times. Thus equipped
he was ready to begin a survey of the heavens.

[Illustration: FIG. 40.--Another portion of the lunar surface, showing a
so-called crater or vast lava pool and other evidences of ancient heat
unmodified by water.]

The first object he carefully examined was naturally the moon. He found
there everything at first sight very like the earth, mountains and
valleys, craters and plains, rocks, and apparently seas. You may imagine
the hostility excited among the Aristotelian philosophers, especially no
doubt those he had left behind at Pisa, on the ground of his spoiling
the pure, smooth, crystalline, celestial face of the moon as they had
thought it, and making it harsh and rugged and like so vile and ignoble
a body as the earth.

[Illustration: FIG. 41.--Lunar landscape showing earth. The earth would
be a stationary object in the moon's sky: its only apparent motion being
a slow oscillation as of a pendulum (the result of the moon's
libration).]

He went further, however, into heterodoxy than this--he not only made
the moon like the earth, but he made the earth shine like the moon. The
visibility of "the old moon in the new moon's arms" he explained by
earth-shine. Leonardo had given the same explanation a century before.
Now one of the many stock arguments against Copernican theory of the
earth being a planet like the rest was that the earth was dull and dark
and did not shine. Galileo argued that it shone just as much as the moon
doe