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KEPLER’S LAWS. 307 
quite a modern science. It dates only from the sixteenth 
century. 
Three great, three brilliant phases, have marked its 
progress. . 
In 1548 Copernicus overthrew with a firm and bold 
hand, the greater payt of the antique and venerable scaf- 
folding with which the illusions of the senses and the 
pride of successive generations had filled the universe. 
The earth ceased to be the centre, the pivot of the celes- 
tial movements ; it henceforward modestly ranged itself 
among the planets; its material importance, amid the 
totality of the bodies of which our solar system is com- 
posed, found itself reduced almost to that of a grain of 
sand. 
Twenty-eight years had elapsed from the day when 
the Canon of Thorn expired while holding in his falter- 
ing hands the first copy of the work which was to diffuse 
so bright and pure a flood of glory upon Poland, when 
Wiirtemberg witnessed the birth of a man who was des- 
tined to achieve a revolution in science not less fertile in 
consequences, and still more difficult of execution. This 
man was Kepler. Endowed with two qualities which 
seemed incompatible with each other, a volcanic imagina- 
tion, and a pertinacity of intellect which the most tedious 
numerical calculations could not daunt, Kepler conjec- 
tured that the movements of the celestial bodies must be 
connected together by simple laws, or, to use his own 
expressions, by harmonic laws. These laws he under- 
took to discover. A thousand fruitless attempts, errors 
of calculation inseparable from a colossal undertaking, 
did not prevent him a single instant from advancing 
resolutely towards the goal of which he imagined he had 
obtained a glimpse. Twenty-two years were employed 
