AMERICA THE OLD WORLD. 
5 
cold. Water, which expands when freezing, is 
the only exception to this rule. The first effect 
of cooling the surface of our planet must have 
been to solidify it, and thus to form a film or 
crust over it. That crust would shrink as the 
cooling process went on ; in consequence of the 
shrinking, wrinkles and folds would arise upon 
it, and here and there, where the tension was too 
great, cracks and fissures would be produced. 
In proportion as the surface cooled, the masses 
within would be affected by the change of tem- 
perature outside of them, and would consolidate 
internally also, the crust gradually thickening by 
this process. 
But there was another element without the 
globe, equally powerful in building it up. Fire 
and water wrought together in this work, if not 
always harmoniously, at least with equal force 
and persistency. I have said that there was a 
time when no atmosphere surrounded the earth ; 
but one of the first results of the cooling of its 
crust must have been the formation of an atmos- 
phere, with all the phenomena connected witli 
it, — the rising of vapors, their condensation into 
clouds, the falling of rains, the gathering of 
waters upon its surface. Water is a very active 
agent of destruction, but it works over again the 
materials it pulls down or wears away, and builds 
them up anew in other forms. As soon as an 
