of his observatory at
Huen, upon the equipment and embellishment of which it is stated he
expended a ton of gold; the splendour and variety of his instruments,
and his ingenuity in inventing new ones, would alone have made him
famous. But it was by the skill and assiduity with which he carried out
his numerous and important observations that he has earned for himself a
position of the most honourable distinction among astronomers. In his
investigation of the Lunar theory Tycho Brahe discovered the Moon's
_annual equation_, a yearly effect produced by the Sun's disturbing
force as the Earth approaches or recedes from him in her orbit. He also
discovered another inequality in the Moon's motion, called the
_variation_. He determined with greater exactness astronomical
refractions from an altitude of 45 deg. downwards to the horizon, and
constructed a catalogue of 777 stars. He also made a vast number of
observations on planets, which formed the basis of the 'Rudolphine
Tables,' and were of invaluable assistance to Kepler in his
investigation of the laws relating to planetary motion.

Tycho Brahe declined to accept the Copernican theory, and devised a
system of his own, which he called the 'Tychonic.' By this arrangement
the Earth remained stationary, whilst all the planets revolved round
the Sun, who in his turn completed a daily revolution round the Earth.
All the phenomena associated with the motions of those bodies could be
explained by means of this system; but it did not receive much support,
and after the Copernican theory became better understood it was given
up, and heard of no more.

We now arrive at the name of KEPLER, one of the very greatest of
astronomers, and a man of remarkable genius, who was the first to
discover the real nature of the paths pursued by the Earth and planets
in their revolution round the Sun. After seventeen years of close
observation, he announced that those bodies travelled round the Sun in
elliptical or oval orbits, and not in circular paths, as was believed by
Copernicus. In his investigation of the laws which govern the motions of
the planets he formulated those famous theorems known as 'Kepler's
Laws,' which will endure for all time as a proof of his sagacity and
surpassing genius. Prior to the discovery of those laws the Sun, though
acknowledged to be the centre of the system, did not appear to occupy a
central position as regards the motions of the planets; but Kepler, by
demonstr