The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1856-1888, 1872-12-14

utterly at the mercy of usurpers.
The NOVEMBER number Of the american Journal
|of Science and Art, contains an abstract of a.
paper by ROBERT MALLET F. r. s., on Volcanic
Energy: Entitled an attempt 10 dereOp ais true
origin and COsmicdi Relations, in which the
author after passing in brief review the principal
theories which in modern times have been pro-
posed to account for volcanic activity, points out
various relations and points of connection between
volcanic phenomena, seismic or earthquake pheI
;nOmena, and the lines of mountain elevation, which
sufficiently Indicate that they are all due to the
play of one set of cosmical forces. though differ
ent in degree of energy, which has been constantly
~lecayIng with time.
lie traces the ways in which the contraction of
)ur globe has been met, from the period of its
original iuidity to the present state: first, by de-
formation of the spheroid. forming generally the
pecan basins and the land; aiterward by the fold
Iings over and elevations of the thickened crust in
to mountain ranges, ETC.; and, lastly, by the
mechanism, which he points out as giving rise to-
volcanic action. The theory of mountain eleya-
ltiOn proposed by C.. Provost was the only true ONE
that which ascribes this to tangential pressuresI
lpropagated through a solid crust of sufficient
to transmit them, those pressures beingi
produced by the relative rate Of contraction of the.
and of the crust; the former being at the
|highertemperature, and havinga higher co-efhcientl
pf contraction for equal loss of heat, tends toE
Shrink away from beneath the crust, leaving the;
latter partially unsupported. This, which dur
ing a much more rapid rate of cooling from higher
temperature of the whole globe and from a thin
crust gave rise in former epochs to mountaini
elevation, in the present state of things gives rise
to volcanic heat. Blythe application of a theorem|
pf Lagrange, the author proves that the earth's
solid crust, however great may be its thickness,
and even if Of materials far more cohesive and
rigid than those of which we must suppose it toI
consist, must, if even to a very small extent left;
unsupported by the shrinking away of thenucleus,
crush up in places by its own gravity and by the
of the nucleus.
This is actually going on, and in this PARTIAL
crushing, at places or depths dependent on the!
material, and on conditions pointed out, thei
author discovers the true cause of volcanic heat.
As the solid crust sinks together to follow down.
after the shrinking nucleus, the toOrk expended
in mutual crushing and dislocation of its parts:
is transformed into heat, by which, at the places
where the crushing sufficiently takes place, thel
material of the rock so crushed and of that ada!
cent to it are heated, even to fusion. The access
OF water to such points determines volcanic erup-s
ton. Volcanic heat. therefore, is one result of
the secular cooling of a teraqueous globe subject
to gravitation, and needs no strange or gratuitous.
hypothesis as to its origin.
He shows, by estimates which allow an ampleE
margin to the best data we possess as to the total
annual vulcanicity of all parts of our globe at!
present, that less than one fourth of the total heat
ut present annually lost by our globe is upon his
theory sufficient to account for it; so that thes
secular cooling, small as it is, now going on is AZ
pr1mIAn mobile, leaving the greater por-
ton still to be ~dissipated by radiation. He alsoE
that to the heat developed by partial tam
perturbations of hypogeal increment of tempera-;
ture which Hopkins has shown cannot be REFEREED
to a cooling nucleus and to differences of conduc-I
tivity alone. He further shows that this view of
the origin of volcanic heat is independent of any
particular thickness being assigned to the earth'sE
solid crust, or to whether there be at present al
fused nucleus, all that is necessary being AZ
hotter nucleus than crust, so that the rate of con-
traction is greater for the former than the latter.
The author then points out that, as the same plays
of tangential pressures has elevated the mountaina
chains in past epochs, the nature of the forces en-
ployed sets a limit to the height of mountains pos;
sible of the materials of our globe. &
Lastly, he brings his views into relation With
vulcanicity produced in like manner in others
planets, or in our satellite, and shows that III
an adequate solution of the singular and
SO far unexplained fact that the elevations uponl
our moons surface, and the evidences of formers
volcanic activity, are upon q scale so vast when
compared with those upon our globe.
Finally, he submits that if his view will acc
for all the known facts, leaving none inex-S
and presenting no irreconcilable condi-l
tions or necessary deductions, then it should be-
as a true picture of nature. 8
II CONSEQUENCE of the complaints which have
been made from time to time, both in the ADvER-s
rIsER and in the native journals, as to the injuri 8
DusIy careless manner in which mail matter be-