78 THE POPULAR SCIENCE MONTHLY. 



infinitesimal in comparison, is not here taken into the calculation. 

 But, were it more considerable, it would not be important in this con- 

 nection, for it falls upon all parts of the earth about equally. 



It is evident, from the present condition of the earth's surface, that 

 at the time it was a molten mass, and for a long time thereafter, it 

 radiated heat into space much more rapidly than it received heat from 

 the sun ; but nevertheless the heat of the sun is, and always has been, 

 offsetting the loss of heat from the earth by radiation to the full ex- 

 tent of the heat which the earth had been receiving from the sun 

 during the time. 



But this sun-heat, this offset to radiation, has not been received by 

 all parts of the earth equally. The equatorial belt, or torrid zone, has 

 always received the most per square foot, or in j^roportion to its area. 

 The two intermediate or temperate zones have received the next largest 

 amount per square foot, or in proportion to their area ; while the polar 

 or frigid zones have received the least per square foot, or in proportion 

 to their area. If the amount of sun-heat received at the equator be 

 rated at 1,000, then, upon the same basis, the average of sun-heat 

 throughout the torrid zone should be rated at 975, the average sun- 

 heat throughout the temperate zones at 757, and the average sun-heat 

 throughout the frigid zones at 454, or less than one half that of the 

 torrid and less than two thirds that of the temperate zones. We speak 

 here, and shall hereafter, of the geographical zones of the earth for 

 the sake of convenience. 



The greatest amount of heat received from the sun and offsetting 

 radiation from the earth, other things being equal, is, of course, as we 

 have seen, at the equator, and less and less every degree north and 

 south of this line to the poles. If, then, the frigid zones have been 

 during all this time receiving the least heat from the sun — the least 

 offset to their own loss of heat by radiation — does it not follow that 

 they were the first parts of the earth sufiiciently cooled to maintain 

 vegetal and animal life ? The inference seems inevitable. 



^»» 



CHEISTIAN AGNOSTICISM. 



By the Eev. Cai^on CUETEIS. 



THE title at the head of this article may appear to some a contra- 

 diction in terms. But it is not really so. And no religious man 

 need shrink from saying : " I am a Christian agnostic. I hold firmly 

 by the doctrine of St. Paul, who exclaims, in sheer despair of fathom- 

 ing the unfathomable, ' O the depth of God ! How unsearchable are 

 his judgments, and inscrutable his ways ! ' I say, with Job and all the 

 great prophets of the Old Testament, ' Canst thou by searching find 



