SOLAR HEAT. 63 



and bows his soiil in prayer, to the principle of fire, 

 which in his ignorance he regards as the giver and the 

 supporter of life. The philosopher finds life and organi- 

 zation dependent upon the powers combined in the 

 sunbeam ; and, examining the phenomena of this 

 wonderful band of forces, he is compelled to acknow- 

 ledge that the flame upon the altar on the 'Persian 

 hills, was indeed a dim shadow of the infinite wisdom 

 which abides behind the veil. 



The present condition of our earth is directly depen- 

 dent upon the amount of heat we receive from the sun. 

 It has frequently been said, that if it were possible to 

 move this planet so much nearer that orb that the 

 quantity of heat would be increased, the circumstances 

 of life would necessarily be so far changed, that all the 

 present races of animals must perish; and that the 

 same result would happen from any alteration which 

 threw us yet further from our central luminary, when, 

 owing to the extremity of cold and the wretchedness of 

 gloom, all living creatures would equally fail to support 

 their organization. 



To move the earth nearer to, or more distant from 

 the sun, is an impossibility ; but it has been argued 

 that those planets which are near to the sun must pos- 

 sess a temperature which would melt our solid rocks, 

 and vaporize the ocean, while Uranus and Neptune 

 must, from their distance from the source of heat, have 

 so small an amount, that water must become solid as 

 the rock, and such an atmosphere as that of the earth 

 exist as a dense liquid. 



It will be shown that according to the physical con- 

 dition of the material substances, so are their powers regu- 

 lated of absorbing and retaining the heat which falls as a 

 radiant power upon their surfaces. Heat rays, in passing 

 through the attenuated medium, of planetary space, lose 

 none of their power this we know from the fact that even 

 the less dense upper region of the earth's atmosphere 

 takes from the solar rays but an exceedingly small 



