JOURNAL AND PROCEEDINGS. 46 
and the difficulties were constantly increasing. Copernicus 
thought that if the sun was chosen as the centre of these plan- 
etary movements, many, if not all the difficulties would dis- 
appear. Hindered by the strong prejudices of many, and more 
or less perplexed with doubt, he hesitated long in declaring his 
convictions. At length with a strong desire to know only the 
truth, he tore himself away from old unsatisfactory theories 
and in imagination, placed himself in the sun, and from thence 
worked out his intricate calculations. From thence the oscil- 
lations of Mercury and Venus became regular revolutions nearest 
to the sun. Next to them, the earth ; then Mars, Jupiter and 
Saturn moving on majestically around the sun. Having satis- 
fied his mind respecting this great fact, he turned to the moon 
to find out what had never before been even suspected, that 
she was a satellite of the earth. The old doctrine of Ptolomey 
with the immovable earth as the centre of all astronomical 
movements, and with circular orbits only, had been woven into 
human learning and society and was not to be easily expelled. 
Copernicus himself had not opposed the circle, so. there were 
difficuties still which some one coming later must solve. He 
had done much to simplify astronomy in removing the centre 
from the earth to the sun. 
It now remained for another to determine the exact curves 
in which the planets moved: the laws which regulate their 
motions and the bond which bound them all together, if such 
a bond existed. God sent Kepler who has been called, 
‘The Legislator of the Heavens,’ a pious and unpre- 
judiced man, who sought by prayer for truth and then 
worked as if prayer was of no avail without work. 
Having adopted the ideas which Copernicus had _pro- 
pounded that the sun was the true centre with the planets, 
including the earth, revolving around him, he selected the 
planet Mars, to discover if possible the true curve, which would 
reveal orbitual motions of the heavenly bodies. After 8 years 
of incessant toil in which he had tested no less than nineteen 
different hypotheses of circular motion, none of which could 
account for the perturbations of the planets, he threw them all 
