so many labourers as to its visible
phenomena and products, and the still greater mass of speculation, good
and bad, on every branch of the subject), by giving a necessarily very
brief and imperfect sketch of my own views as in that Paper in part
developed. It will first be necessary to retrace our steps a little, in
order to gain such a point as shall afford us a fuller view of the whole
problem before us.

It is not necessary to dilate, even did space allow, upon the many
points which bind together Earthquakes and Volcanoes as belonging to the
play of like forces. These are generally admitted; and in various ways,
more or less obscure, geologists generally have supposed some relations
between these and the forces of elevation, which have raised up mountain
chains, etc.

No one, however, that I am aware of, prior to myself, in the Paper just
alluded to, has attempted to show, still less to prove upon an
experimental basis, that all the phenomena of elevation, of volcanic
action, and of Earthquakes, are explicable as parts of one simple
machinery--namely, the play of forces resulting from the secular cooling
of our globe. We have seen that, on the whole, both Earthquakes and
Volcanoes follow along the great lines of elevation of our surface. Any
true solution of the play of forces which has produced any one of those
three classes of phenomena must connect itself with them all, and be
adequate to account for all. And this would have earlier been seen, had
geologists generally framed for themselves any correct notions of the
mechanism of elevation itself, and seen its real relation with the
secular cooling of our planet. But the play of forces resulting from
this secular cooling has never, until very recently, been adequately or
truly stated. The arbitrary assumption and neglect of several essential
conditions by La Place, in his celebrated Paper "On the Cooling of the
Earth," in the fifth volume of the "Mecanique Celeste," and the
arbitrary and unsustainable hypothesis of Poisson upon the same subject,
have tended to retard the progress of physical Geology as to the nature
of elevation: the first, by leaving the geologist in doubt as to whether
our globe were cooling at all; the second, by suggesting distorted
notions as to the mode of its cooling and consolidation. On the other
hand, neither geologists nor mathematicians generally have framed for
themselves any clear notions of the mechanism of elevation. Had a true
c