ASTRONOMY. 
crease his attachment to there, he made a 
journey into Germany, where he formed 
connections, and entered into a corres- 
pondence with some of the most eminent 
astronomers of that country, particularly 
with the landgrave of Hesse, who received 
hita in the most flattering manner, and re- 
commended him to the notice of his sove- 
reign. Becoming by this means better 
known, on his return to Denmark, Frederic 
II. gave him the little island of Huen, at 
the entrance of the Baltic, where he built 
an observatory, under the name of Urani- 
burg, and in which, during a course of 20 
years, he made a prodigious number of ob- 
servations. His tranquillity, however, in 
this happy retreat, was at length inter- 
rupted ; for soon after the death of Frede- 
ric,. which happened in 1596, he was de- 
prived, through the aspersions of some en- 
vious and malevolent persons, of his pen- 
sion and establishment, and was not even 
allowed to follow his pursuits at Copenha- 
gen ; a minister of that time, of the name of 
Walchendorp, having forbid him to conti- 
nue his observations. Happily, however, 
he found a powerful protector in the Em- 
peror Rodoiphus II., who ordered him to 
be properly provided for at his own ex- 
pense, and gave him a commodious house 
at Prague. After residing in this city till 
the year 1601, he was taken off by a sud- 
den death, in the midst of his labours, and 
at an age while he was yet capable of ren- 
dering great services to astronomy. This 
great man, as is well known, was the in- 
ventor of a kind of semi Ptolemaic system 
of astronomy, that was afterwards called by 
his name, and which he vainly endeavoured 
to establish instead of the Coperniean, or 
true system. But though he was not happy 
in this respect, he has been of great use to 
astronomy, by his numerous observations 
and discoveries. 
Tycho Brahe, in thelafterpart ofhis life, 
had for his disciple and assistant, the cele- 
brated Kepler, who was bom in 1571, at 
Wiel, in the duchy of Wirtemberg, and was 
one of those rare characters that appear in 
the world only at particular times, to pre- 
pare the way for new and important dis- 
coveries. Like his master Tycho, he ap- 
pears to have attached himself to the 
science at a very early age; and if it be 
the privilege of genius to change received 
ideas, and to announce truths which had 
never before been discovered, he mayjustly 
be considered as one of the greatest men 
■that had yet appeared. Hipparchus, Ptolemy, 
Tycho Brahe, and even Copernicus himself, 
were indebted for a great part of their 
knowledge to the Egyptians, Chaldmans, 
and Indians, who were their masters in 
this science ; but Kepler, by his own talents 
and industry, has made discoveries of which 
no traces are to be found in the annals of 
antiquity. See Braiie. 
This great man, after seventeen years of 
meditation and calculation, having had the 
idea of comparing them with the powers of 
the numbers by which they are expressed, 
he found that the squares of the times of 
the revolutions of the planets are to each 
other as the cubes of their mean distances 
from the sun ; and that the same law ap- 
plies equally to their satellites. See Kep- 
ler. 
At the same time also that Kepler, in 
Germany, was tracing the orbits of the 
planets, and settling the laws of their mo- 
tions, Galileo (who was born at Pisa, in 
Italy, in 1564) was meditating upon the 
doctrine of motion in general, and investi- 
gating its principles ; and from the admira- 
ble discoveries which he made in this 
branch of the physico-meehanical sciences, 
Newton and Huygens were afterwards en- 
abled to derive the most brilliant and com- 
plete theories of all the planetary mo- 
tions. 
About this period also, a fortunate acci- 
dent produced the most marvellous instru- 
ment that human industry and sagacity 
could have ever hoped to discover; and 
which, by giving a far greater extension and 
precision to astronomical observations, shew- 
ed many irregularities and new pboenome- 
na, which iiad hitherto remained unknown. 
This invention was that, of the telescope, 
which was no sooner known to Galileo, 
than he set himself about to improve it ; and 
the discoveries he was by this means ena- 
bled to make, were as new as they were 
surprising. 
The face of the moon appeared full of ca- 
vities and asperities, resembling vallies and 
mountains. The sun, which had generally 
been considered as a globe of pure fire, was 
observed to be sullied by a number of dark 
spots, which appeared on various parts of 
his surface. A great number of new stars 
were discovered in every part of the hea- 
vens; the planet Jupiter was found to be 
attended with four moons, which moved 
round him in the same manner that our 
moon moves round the earth ; the phases of 
Venus appeared like those of the moon, as 
had before been concluded by Copernicus, 
