76 
bearings. So that at some place or other this solid floating crust 
must be brought into a state of strain, and if there be a weak 
or a soft part, a crack will at last take place. When this hap- 
pens, down goes the land on the heavy side and up on the light 
side. Now this is exactly what took place in the earthquake 
[see three pp. ante] which raised the Ullah Bund in Cutch” (18). 
This view of the causes of earthquakes, and of elevations and 
subsidences of the land, accounts at the same time for volcanic 
eruptions, the volcano being a vent for the passage of heated 
and melted matter, which the elevatory pressure of the liquid 
below tends to throw up. It has with much probability been 
suggested that the reason volcanoes and the originating centres 
of earthquakes are almost universally on the borders of seas and 
oceans, is that at such positions the accumulation of transported 
matter, whether due to sub-aerial detritus, or to river-deposit 
at deltas, would attain its greatest amount. Further, as is much 
insisted upon in Ilerschel’s lecture, the eruption of scoriae and 
lava from the mouths of volcanoes, in consequence of the upward 
pressure of the fiery liquid below, is a kind of compensation for 
the downward transfer of material by detritus and river-deposit, so 
that upon the whole the quantity of solid matter above the 
ocean-level is likely to be pretty nearly constant. 
These are all the points relating to the forces concerned in 
the phenomena of earthquakes and volcanoes, that I have 
thought it necessary to direct attention to. This antecedent 
consideration of the nature of those forces was required for my 
purpose, because I am about to propose a theory which attributes 
the Deluge to the operation of forces of the same kind, differing 
only in degree and in the superficial extent of their action. 
Also I regarded it as a matter of importance to show that the 
character of the forces I shall have to deal with has received 
countenance from the views of so eminent a philosopher as 
Herschel, although the supposed applicability of such forces to 
account for the circumstances recorded in Scripture relative to 
the Deluge is altogether an independent hypothesis, for which 
I alone am responsible. 
The next step in Division II. of the general argument is to 
indicate, first, the possible origination of physical operations which 
might have the particular effect of producing a deluge, and then 
to show in what manner such operations might generate the 
phenomena recorded in Scripture relative to the Noachian 
Deluge. The explanations I am about to propose relative to 
these two points will rest on the assumption that the earth’s 
internal heat is not a constant quantity, but susceptible of varia- 
tions partaking of a sudden and violent character. I do not 
