338 FROM NEBULA TO NEBULA 



How much more reasonable to say that when under heavy 

 compression water is naturally cold, and as naturally re- 

 mains so while the load stays on. 



The theory that energy is something apart from 

 matter and that heat is energy, whereas its absence is a 

 negation, does not bear out in practice. If you will take 

 two exactly similar metallic vessels, fill both of them with 

 water and tightly seal them and then place one of them 

 over a hot flame and the other out in the bitter cold, you 

 will learn that both alike will rend themselves. One will 

 burst by gaseous expansion due to heat, the other by the 

 swelling of the water into solid ice; in the former case 

 you must wait until the heat accumulates, in the latter, 

 until the last vestige of it has departed! The result in 

 both cases is the same. Why then do they call heat en- 

 ergy, but coldness not? Again, to produce a quart of 

 liquid air requires the waste of a great deal of heat, but 

 the former, by virtue of its frigidity, will accomplish 

 wonders that heat could never begin to do, or undo. The 

 Conservationists will tell you that the work done by the 

 liquid air is in fact a compensation for the thermal en- 

 ergy expended in its liquefication, but what about the 

 work of condensation on the sun performed by the cold 

 of space? Is the inexhaustible cold of space, also, a 

 ' ' product of thermal expenditure ' ' 1 



The conductivity of earthy matters is notoriously 

 poor, that of marble, for example, being only about 1-100 

 that of silver, and brick-earth only about 1-200 of the 

 same. The thickness of a few inches of clay in the walls 

 of a crucible will protect the workmen from a fire within 

 it of two thousand degrees, and more. Now, the temper- 

 ature of the earth's crust varies at the snail's pace of 

 only one degree for 60 feet of earthy matter. Which, I 

 pray, is the more reasonable inference : that the central 

 heat is oozing out at this amazingly odd rate, or that the 

 temperature gradient is due to the fact of gravistatio 

 heat being generated in situ? Anent this subject, let me 

 quote the testimony of Alfred Eussell Wallace (Is Mars 

 Habitable, p. 40) : 



