8 



THE STORY OF THE EARTH AND MAN. 



proved telescopes to bo really clusters of stars, and 

 it was inferred that the others might be of like 

 character. The spectroscope has, however, more 

 recently shown that some nebulse are actually gaseous ; 

 and it has even been attempted to demonstrate that 



F^gs. 1 to 5. Ideal sections illustrating the Genesis of the Earth, 



Fig. 1. A vaporous world. 



Fig. 2. A world with a central fluid nucleus (6) and a photosphere (a). 



Fig. 3. The photosphere darkened, and a solid crust (c) and solid 

 nucleus {d) formed. 



Fig. 4. Water {e) deposited on the crust, forming a universal ocean. 



Fig. 5. The crust crumpled by shrinkage, land elevated, and the water 

 occupying the intervening depressions. 



The figures are all of uniform size ; but the circle (A) shows the 

 diameter of the globe when in the state of fig. 1, and that marked (B) 

 its diameter when in the state of fig. 5. In all the figures (a) represents 

 vapour or air; (6) liquid rock; (c) solid rock as a crust; (d) solid 

 nucleus; {*) water. 



