254 THE EIDDLE OF THE UNIVEESE. 



each other at inconceivable speed, enormous quantities 

 of heat are liberated, while the pulverised masses are 

 hurled and scattered about space. The eternal drama 

 begins afresh — the rotating mass, the condensation of 

 its parts, the formation of new meteorites, their com- 

 bination into larger bodies, and so on. 



II. MONISTIC GEOGENY. 



The history of the earth of which we are now going 

 to make a brief survey is only a minute section of the 

 history of the cosmos. Like the latter, it has been 

 the object of philosophic speculation and mythological 

 fantasy for many thousand years. Its true scientific 

 study, however, is much younger ; it belongs, for the 

 most part, to the nineteenth century. The fact that 

 the earth is a planet revolving round the sun was 

 determined by the system of Copernicus (1543) ; 

 Galilei, Kepler, and other great astronomers, mathe- 

 matically determined its distance from the sun, the 

 laws of its motion, and so forth. Kant and Laplace 

 indicated, in their cosmogony, the way in which the 

 earth had been developed from the parent sun. But 

 the later history of the earth, the formation of its 

 crust, the origin of its seas and continents, its 

 mountains and deserts, was rarely made the subject 

 of serious scientific research in the eighteenth century, 

 and in the first two decades of the nineteenth. As a 

 rule, men were satisfied with unreliable conjectures, 

 or with the traditional story of creation ; once more 

 the Mosaic legend barred the way to an independent 

 investigation. 



In 1822 an important work appeared, which followed 

 the same method in the scientific investigation of the 



