COSMOGONIES 115 



time was not yet ripe. Bruno was burnt at the 

 stake for his speculations, and Galileo almost 

 shared the same fate ; and though Kepler for- 

 mulated a theory that the sun exercised a magnetic 

 influence, and that the planets were made to re- 

 volve by a whirling medium, and Descartes 

 brought forward his theory of "tourbillons" or 

 vortices, which was afterwards borrowed by 

 Swedenborg, not till the time of Kant can there 

 be said to have been a really successful attempt 

 to construct a cosmogony. 



With Kant the science of cosmogony may be 

 said to have started. 



Kant was a follower of Democritus and Epicurus, 

 and he tried to construct the cosmos, or at least the 

 solar system, from the motion of atoms and mole- 

 cules ; but he had Kepler's and Newton's laws to 

 guide him, and he brought to the task much more 

 mechanical and astronomical knowledge than were 

 possessed by the two Greek philosophers. He 

 postulated merely atoms, gravitation, and molecular 

 repulsion, and with these he attempted to make the 

 solar system. Under the influence of gravitation 

 and molecular repulsion, the atoms would rush to- 

 wards the centre and clash with each other, and, 

 according to his views, the collisions and jostlings 

 would cause the whole mass to revolve, and the 

 revolution, again, would throw off by centrifugal 



