410 VOLTAIC ACTION, AND 



scence, into the planetary space, the tempera- 

 ture of which he estimates at about 58 F. 

 due to radiation from the sun and fixed stars. 



By a long and laborious series of mathema- 

 tical investigation, he arrived at the conclusion 

 " that the earth once heated to any temperature 

 whatever, and thus plunged into a colder me- 

 dium than itself, would cool no more in 1,280,000 

 years, than a globe of a foot in diameter com- 

 posed of the like materials, and placed in the 

 same circumstances would in a second of time, 

 -that is to say, in this immense time, no appre- 

 ciable variation would take place." (Ann. de 

 Chim. et de Phys., October, 1834.) 



The absurdity of supposing that " all the 

 caloric of the earth below the invariable stra- 

 tum (which does not extend much beyond one 

 hundred feet below the surface,) comes from a 

 central fire," is too obvious to require a serious 

 refutation. 



If there have been two thousand volcanic erup- 

 tions every century, according to the estimate 

 of Mr. Lyell, it would give 25,600,000 eruptions 

 in 1,280,000 years: yet the temperature of the 

 globe has not sensibly diminished in that time 

 according to the estimate of Fourier. But if 

 25,600,000 volcanic eruptions, together with 

 several thousand times as many hot springs, 

 had proceeded from a central fire, the reduction 

 of the earth's temperature must have been enor- 

 mous. It is therefore evident, that the whole 



