no THE SPHERICITY OF THE EARTH. 



We now know why, for a whole series of centuries, men 

 would not follow in the footsteps of Aristotle, who was the 

 first to establish theoretically the sphericity of the earth. 



The discovery of the 'New World, and the voyages of 

 circumnavigation which rapidly succeeded one another, 

 demonstrated, not only that inhabitants there are whose 

 feet are opposite to ours, but that the earth does not rest 

 upon any species of support ; that it floats, like a star, freely 

 in space. 



The ice was broken. The question of the earth's figure 

 was revived, and, this time, discussed in a new light. 



Is the earth perfectly round ? 



Copernicus never doubted it ; he who was the first, after 

 Pythagoras, to represent our planet as revolving round the 

 sun. The geometrical sphericity of the earth wonderfully 

 harmonised with the perfect circles in which he supposed 

 the planets to move. Kepler, who had first laid a sacri- 

 legious hand on the holy figure of the circle, and on the 

 circular orbits of the stars, never ventured, however, to 

 dispute the perfect rotundity of the earth ; it appeared to 

 him a matter beyond all controversy. Galileo was the first 

 to hazard a doubt. But this doubt became a certainty only 

 through the labours of Huygens. 



Galileo, who died in the very year that Newton was born 

 (1642), had discovered, as we know, that all bodies, in 

 falling, obey an uniformly accelerative force, called gravitation^ 

 and that the space traversed increases as the square of 



