MATERIAL UNIVERSE. 55 



CHAPTER IV. 



BEFORE proceeding further, it becomes us to 

 pause a moment, and consider, somewhat more 

 in detail, the probable condition of the earth, 

 when the waters around it had been condensed 

 into a liquid form on its surface. Let us suppose, 

 then, by way of illustration, a number of metal- 

 lic bodies, combined in a fluid state, and made 

 to assume a globular form, to be projected from 

 the earth into the atmosphere. Let us suppose 

 this fluid metallic mass to be capable of retaining 

 its caloric of fluidity for a definite length of 

 time. We know that this body, as it gradually 

 cooled, would attract oxygen from the atmo- 

 sphere, and would soon be coated with rust, or 



