THE GENESIS OF THE EARTH. 9 



tliey aro probably undergoing change fitting tliem to 

 become systems. This has served to revive the 

 nebular hypothesis, which has been further strength- 

 ened by the known fact that the sun is still an incan- 

 descent globe surrounded by an immense luminous 

 envelope of vapours rising from its nucleus and con- 

 densing at its surface. On the other hand, while the 

 sun may be supposed, from its great magnitude, to 

 remain intensely heated, and while it will not be 

 appreciably less powerful for myriads of years, the 

 moon seems to be a body which has had time to 

 complete the whole history of geological change, and 

 to become a dry, dead, and withered world, a type 

 of what our earth would in process of time actually 

 become. 



Such considerations lead to the conclusion that the 

 former watery condition of our planet was not its first 

 state, and that we must trace it back to a previous 

 reign of fire. The reasons which can be adduced 

 in support of this are no doubt somewhat vague, and 

 may in their details be variously interpreted ; but at 

 present we have no other interpretation to give of that 

 chaos, formless and void, that state in which '^ nor 

 aught nor nought existed,^' which the sacred writings 

 and the traditions and poetry of ancient nations concur 

 with modern science in indicating as the primitive 

 state of the earth. 



Let our first picture, then, be that of a vaporous 

 mass, representing our now solid planet spread out 

 over a space nearly two thousand times greater in 



