170 TIIK CANADIAN NATURALIST. [June 



generate great amounts of elastic fluids by their fusion, earth- 

 quakes and volcanic eruptions may result, and these — otjier 

 things being equal — will be most likely to occur under the more 

 recent formations." (C'inodian Jourivil^ May, 1858, vol. iii. p. 

 207.) 



The same views are insisted upon in a paper " On some Points 

 in Chemical Geology" (Quart. Jour. Geol. Soc, London, Nov. 

 1859, vol. XV. page 594,) and have since been repeatedly put 

 forward by me, with farther explanations as to what I have 

 designated above, the ruins of the crust of anhydrous and primi- 

 tive igneou." rock. This, it is conceived, must, by contraction in 

 cooling, have become porous and permeable, for a considerable 

 depth, to the waters afterwards precipitated upon its surface. In 

 this way it was prepared alike for mechanical disintegration, and 

 for the chemical action of the acids, which, as shown in the two 

 papers just referred to, must have been present in the air and 

 the waters of the time. It is, moreover, not improbable that a 

 yet unsolidified sheet of molten matter may then have existed 

 beneath the earth's crust, and may have intervened in the 

 volcanic phenomena of that early period, contributing, by its 

 extravasation, to swell the vast amount of mineral matter then 

 brought within aqueous and atmospheric influences. The earth* 

 air, and water thus made to react upon each other, constitute 

 the first matter from which, by mechanical and chemical transfor- 

 mations, the whole mineral world known to us has been produced. 



It is the lower portions of this great disintegrated and water- 

 impregnated mass which form, according to the present hypo- 

 thesis, the semi-liquid layer supposed to intervene between the 

 outer solid crust and the inner solid and anhydrous nucleus. In 

 order to obtain a correct notion of the condition of this mass, both 

 in earlier and later times, two points must be especially considered, 

 the relntion ol temperature to depth, and that of solubility to 

 pressure. It being conceded that the increase of temperature in 

 descending in the earth's cru:>t is due to the transmission and 

 escape of heat from the interior, Mr. Hopkins showed mathe- 

 matically that there exists a constant proportion between the 

 eff'ect of internal heat at the surface and the rate at which the 

 temperature increases in descending. Thus, at the present time, 

 while the mean temperature at the earth's surface is augmented 

 only about one-twentieth of a degree Fahrenheit, by the escape 

 of heat from below, the increase is to be found to be equal to 



