GBAVISTATIC HEAT 295 



sun as our earth is, consequently he receives only 1-27 as 

 much solar heat, area for area, and the ether that sur- 

 rounds him is colder than liquid air. Why, I insist again, 

 is he still hot, even to glowing? Shall we follow the ex- 

 ample of the Conservationists and lazily sit down and 

 wait for the planet to cool, or shall we not rather seek 

 explanation for the phenomenon in routine natural pro- 

 cesses? 



By actual experiment physicists have demonstrated 

 again and again that the metal, lead, can be liquefied in 

 the hydraulic press. They interpret this phenomenon in 

 the light of their doctrine of conservation as signifying 

 that in its molten state the metal returns just as many 

 units of heat, cmd no more, as the mechanical energy de- 

 voted to its compression. In their haste and obsession 

 it seems never to have occurred to any of the experi- 

 menters to watch and wait to see whether the lead will 

 cool off or not ; they are content to accept the traditions 

 of their profession as to that. As in the case of the vacu- 

 um-tube experiment they prejudge the issue and refuse 

 to be set right. 



But let us reason the thing out in a common-sense 

 way. Suppose the experiment to have taken place up to 

 the point where the lead is liquefied, in the cylinder, and 

 still under the full pressure of the piston. We will now 

 assume, to begin with, the possibility that, given time, the 

 lead will cool off and become solid, notwithstanding the 

 continuance of the pressure. At this latter stage imagine 

 the piston to be undamped completely and then immedi- 

 ately reclamped with precisely the same effort as in the 

 first instance, what effect will the proceeding have on 

 the lead? Will the latter be liquefied afresh? How sot 

 Surely the second clamping, by merely restoring the 

 former conditions, cannot compress the ingot to less com- 

 pass than before ; and without accomplishing this much, 

 according to general acceptation, the lead must remain 

 in the solid state. Alternatively, suppose the metal in 

 this case should nevertheless become liquefied; then in 

 the name of reason why did it not stay liquid in the first 

 place? Again, if no change at all should occur and the 



