T. S. Hunt.on Voleanie Action. 25 
fluids by their fusion, earthquakes and volcanic eruptions may 
result, and these—other things being equal—will be most likely 
to occur under the more recent formations.” (Canadian Journal, 
May, 1858, vol. iti, 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 agneous 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 
apers just referred to, must have been present in the air and 
the waters of the time. It is, moreover, not improbable that a 
et unsolidified sheet of molten matter may then have existed 
eneath the earth’s crust, and may have intervened in the vol- 
canic phenomena of that early period, contributing, by its ex- 
travasation, to swell the vast amount of mineral matter then 
brought within aqueous and atmospheric influences. The earth, 
air, and water nade to react upon each other, constitute 
the first matter from which, by mechanical and chemical trans- 
— the whole mineral world known to us has been pro- 
| 
due : 
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. 
Tn 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 relation of temperature to depth, and that of 
_ solubility to pressure. It being conceded that the increase of 
temperature in descending in the earth’s crust is due to the 
transmission and basa of heat from the interior, Mr. Hopkins 
ho ically that there exists a constant proportion 
between the effect 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 escape of heat from below, the increase is to be found 
e 
