lass;
the perspective; the trunk; the cylinder. The appellation _telescope_
was given it by Demisiano.

Galileo next directed his attention to the construction of telescopes,
and applied his mechanical skill in making instruments of a larger size,
one of which magnified _eight_ times. 'And at length,' he writes,
'sparing neither labour nor expense, he completed an instrument that was
capable of magnifying more than _thirty_ times.'

Galileo now commenced an exploration of the celestial regions with his
telescope, and on carefully examining some of the heavenly bodies, made
many wonderful discoveries which added greatly to the fame and lustre of
his name.

The first celestial object to which Galileo directed his telescope was
the Moon. He was deeply interested to find how much her surface
resembled that of the Earth, and was able to perceive lofty mountain
ranges, the illumined peaks of which reflected the sunlight, whilst
their bases and sides were still enveloped in dark shadow; great plains
which he imagined were seas, valleys, elevated ridges, depressions, and
inequalities similar to what are found on our globe. Galileo believed
the Moon to be a habitable world, and concluded that the dark and
luminous portions of her surface were land and water, which reflected
with unequal intensity the light of the Sun. The followers of Aristotle
received the announcement of these discoveries with much displeasure.
They maintained that the Moon was perfectly spherical and smooth--a vast
mirror, the dark portions of which were the reflection of our
terrestrial mountains and forests--and accused Galileo 'of taking a
delight in distorting and ruining the fairest works of Nature.' He
appealed to the unequal condition of the surface of our globe, but this
was of no avail in altering their preconceived notions of the lunar
surface.

Perhaps the most important discovery made by Galileo with the telescope
was that of the four moons of Jupiter. On the night of January 7, 1610,
when engaged in observing the planet, his attention was attracted by
three small stars which appeared brighter than those in their immediate
neighbourhood. They were all in a straight line and parallel with the
ecliptic; two of them were situated to the east, and one to the west of
Jupiter. On the following night he was surprised to find all three to
the west of the planet, and nearer to each other. This caused him
considerable perplexity, and he was at a loss t