Where did Life Begin f 9 



probable condition of the earth previous to 

 the advent of any sort of life upon Its sur- 

 face. A large portion of those who have 

 formed any Intelligent opinions, in the light 

 of modern thought and Investigation, upon 

 the subject of cosmogony, believe and hold 

 very firmly that the earth was at one time an 

 intensely hot globe — Indeed a molten mass, 

 and that in the lapse of time it has cooled 

 down by radiation to its present temperature. 

 It is not at all necessary for the purposes of 

 the present inquiry to examine the so-called 

 nebular theory, nor even to ask when or how 

 this globe became so heated, nor to what 

 extent It has now become cooled, nor need 

 we inquire whether the earth is now but a 

 molten mass covered with a comparatively 

 thin crust, or has cooled and hardened to its 

 very centre. It is Important, however, to 

 have it understood at the outset that the 

 facts and considerations here presented are 

 addressed to those, and those only, who have 

 reached and adopted the conclusion that this 

 globe, at some time in the process of its for- 

 mation and development, passed through a 



