GRAVISTAT1C HEAT 63 



What is true of the sun is only in less degree true 

 of the earth. As \ve descend we find the temperature 

 uniformly increasing one degree for about every sixty 

 feet of depth. Current theory lays this increase to con- 

 duction from the fires within, whereas I claim precisely 

 the reverse, namely, that the fancied fires are due to 

 gravistatic heat, that is, heat caused by gravitational 

 pressure. That current theory is in this instance wrong 

 is sufficiently demonstrated, I think, by the uniformity 

 of the temperature gradations, the heat increasing 

 KEGULARLY. How comes it that science has ignored this 

 conclusive objection to its accepted theory? Everyone 

 knows that the conductivity of clay is very low, and 

 that the thickness of a single foot of it around a blast 

 furnace will protect the workmen from its intensity. 

 The difference may be as much as two thousand degrees 

 between the temperature inside of the furnace and that 

 on the outer face of its wall. What words, then, can 

 \ve have but of disdain for a theory which teaches that 

 a temperature of seventy degrees will avail to penetrate 

 a layer of earthy matter sixty feet in thickness at the 

 cost of only one degree ! Let those who still think other- 

 wise give us some formula as the basis of their opinion. 



In the last preceding chapter I intimated that I 

 would recur to the consideration of the refractory ag- 

 glomeration about the sun's center of gravity. It is 

 evident that in the heat-generating process above de- 

 scribed, tbe more refractory substances would resist 

 volatilization longer than others, hence explosions aris- 

 ing from them would naturally be cataclysmic, and 

 their recurrence tend to more or less regular periodicity. 

 To this I attribute the sun-spot phenomena; and the 

 tropical position of the maculae I lay to the location of 

 this "knot," 



