ARTIFICIAL STONY SUBSTANCE. 



231 



substances on each other is most energetic, the mass, though 

 still fluid, acquires suddenly a great degree of solidity ; the 

 heat is even increased in its intensity ; and the matter after- 

 ward passes almost wholly to a state of insolubility. Th« 

 latter property, acquired by a mixture intended to produce 

 very soluble salts, proves, that the penetration of the earth 

 by the water and acid must have been very great, since the 

 whole mass forms only a stony compound. 

 The stones to which I here allude, though having in ap~ a stone si- 



pearance all the properties of those I have just described, milarmap- 



h. ,, ... *. , • • it. .rx i pearance, but 



ave not the quality ot being insoluble. On the contrary no t insoluble. 



I prevent their passing to this state, as then I could not 

 make use of them. But as this compound has all the ex- 

 ternal characters of the hardest stones, except that it is not 

 insoluble, I conceived it would not be uninteresting to see an 

 artificial stony substance, which some peculiar properties 

 might render useful. For instance, as it may be softened Applicable to 

 by a heat superior to that of boiling water, might it not be different us«». 

 employed with much advantage for fastening iron or wood 

 in stone, casting statues, moulding vases, and many other 

 purposes, that experience would point out ? It is true that 

 substances formed of this stony paste must not be exposed 

 to wet. 



Another consideration, that has led me to suppose this new c ause f Vl ,j_ 

 stony compound would not be viewed with indifference, is, canic erupti- 

 that the theory of its formation, and its analogy with the "' 

 stones of solfaterras, render it unnecessary for us to have re- 

 course to the hypothesis of subterranean fires kept up by 

 combustible matters, to explain the eruptions of volcanoes. 



In fact, since water alone, by passing instantaneously from 



the liquid to the solid state, can give rise to the evolution of 



so very considerable a degree of heat, may it not be the 



immediate cause of volcanic eruptions? Is it not like- interior heat of 



the Eaitb, 

 wise the slow and gradual passage of water to the solid state, 



that produces the heat kept up at great depths in the inte- 

 rior of the globe ? Lastly, is not the heat developed in ani- an( j or g an ; e 

 nial and vegetable organization equally owing to water ? bodies. 



SCIENTIFIC 



