GALILEO. 
his own reflections on the nature of refrac- 
tion, discovered the construction of that 
instrument. Tiie next day, after he had 
solved the problem of its construction, he 
made such an instrument, and by the atten- 
tion which he paid to its perfection and im- 
provement, may justly be considered as the 
second inventor of the telescope. He now 
turned his instrument towards the heavens, 
and discovered unheard of wonders. He 
perceived the surface of tire moon not to be 
smooth, but rough, and full of prominences 
and cavities. The milky way he found to 
be an assemblage of fixed stars invisible to 
the naked eye. Venus he found to vary in 
its phases like the moon. The figure of 
Saturn he observed to be oblong, and ima- 
gined that it consisted of three distinct 
parts, one spherical in the midst, and two 
lesser ones on the sides, which afterwards 
appeared to be only the ansce, or extreme 
parts of Saturn’s ring. Jupiter he saw sur- 
rounded with four moons, which in honor 
of the Duke de Medici he called Medicean 
stars, and scon perceived that by means of 
their frequent eclipses, geographic;;! longi- 
tudes might be found. On the. sun’s disk 
he perceived spots, from the motion of 
which lie inferred that the sun revolved on 
its axis. 
ft was while he was pursuing these disco- 
veries, that he was invited to Florence, 
where, as we have seen, he bad leisure 
afforded him to devote himself to his ma- 
thematical and philosophical studies, with- 
out being obliged to attend to the duties of 
his professorship. In a very few years, 
however, his tranquillity was disturbed by 
the ignorant and bigoted clergy, on account 
of the zeal which he discovered for illus- 
trating and confirming the truth of the 
Copernican system. That system they 
maintained to be fabe and heretical, as be- 
ing contrary to the plain and express lan- 
guage of, the scriptures ; and by their com- 
plaints agai<t him to the Inquisition at 
Rome, rendered it necessary for him, in 
the year 1615, to appear in that city to jus- 
tify himself. According to letters written 
from Rome, by the learned Anthony Que- 
zenghi, Galileo did not lose his courage on 
this occasion, but in numerous companies 
of men' of letters and others, defended the 
Copernican doctrine with a force of argu- 
ment which persuaded many of its truth 
and reasonableness, and si’enced the objec- 
tions of others who would not be convinced. 
When he attended the Inquisition, how- 
ever, he was not suffered to enter into any 
explanations, but was directly accused of 
heresy for maintaining the two propositions, 
that the sun is the centre of the world, and 
immovable by a local motion, and that the 
earth is not the centre of the world, nor 
immoveable, but moves with a diurnal mo- 
tion. These propositions he was ordered 
by a decree of the Inquisitors to renounce, 
and not to defend them either in conversa- 
tion or writing, or even to insinuate them 
into the minds of any persons whomsoever. 
Most accounts concur in stating, that, on 
this occasion, he was committed to the pri- 
son of the Holy Office, where he was con- 
fined for about five months ; but according 
to other accounts, he was treated with 
greater mildness, and only threatened with 
imprisonment if ire proved refractory. Be 
that as it may, he was not permitted to 
quit Rome until he had promised to con- 
form himself to the decree of the Inquisi- 
tion ; and it is probable that his sentence 
would have been more severe, bad not the 
Grand Duke of Tuscany warmly interested 
himself on his behalf, as well as some per- 
sons of high rank and influence at the papal 
court. 
Galileo now returned to his studies, in 
which his astronomical observations, and 
other happy discoveries served to establish 
most completely and satisfactorily the truth 
of his obnoxious opinions. From time to 
time he laid before the public an account 
of his discoveries, with such remarks and 
inferences as tended to point out the natu- 
ral conclusions to be drawn from them. 
At length, in the year 1632, he ventured 
to publish at Florence, his famous “ Dia- 
logues on the two greatest systems of the 
World, the Ptolemaic and Copernican ;” in 
which he produced the strongest arguments 
in favour of both systems, without express- 
ing a decided' opinion which of them was 
the true one, but not without such insinua- 
tions in favour of the Copernican as suffici- 
ently indicated its superior reasonableness 
and his own belief in it. Tiiese dialogues, 
likewise, contain some keen strokes of rail- 
lery against the Aristotelians, for their 
bigoted and servile attachment to every 
hypothesis of their master. 
Scarcely had this work made its appear- 
ance before the cry of heresy was raised 
more loudly than ever against Galileo, and 
he was again cited to appear before the tri- 
bunal of the Inquisition, in the year 1633. 
Though now seventy years of age, he was 
obliged to submit to the persecuting man- 
date, and on his arrival at Rome was first 
