The Portland daily press., 1868-03-30
Terms $500 per aaaa.,.,,s, In advance.

soning.y Rather perhaps l ought to saw thar
| he did not consider ice capable of expansion
when at the temperature OF 32 degrees, be-
cause in the second case, he says distinctly
ehat 1t did contract-and of course, then. it
| was capable of expanding while yet in the
sohe state. The phenomenon OF some Of the
denser PuutoDlc rocks OF the paleozoc and
mesozolc geologic ages, compared with recent
loneous ELECTIONS from volcanoes have been
rett rred to the action of chemical forces un-
der the enormous pressure of a deep sea.
Prol. Hopkins OF Cambridge, England, assures
US that the lower mineral strata comprising
the earth's crust, would require far higher
temperature to fuse them, than those which
lie near the surface. We know we'll enough
what is the department of carbon gas under
pressure, and that sulphuric ether under one
atmospheric pressure barely remains fluid
Name teils us that during the extreme cold of
Tue Arctic winter when the thermometer
stood at seventy degrees below zero cbloro-
form froze, and that the oils of sassafras. iIni-
per, cubebs, and winter-green thickened to a
point between liquidi;y and soidifcation.
and that ice resembled granite in hardness
1t appears to me therefore, that there must
be difference in the density of ice freezing
at 81 degrees above zero, and when exposed
to temperature so tar belolp it. 1t is 10 this
hypothetical density that refer that wonder
tul phenomenon OF sinking ice so often no.
ticed by the arctic navigator. This phenom-
enon could not occur unless the ice be denser
than water, and it cannot be denser than wa
ter unless its ultimate atoms are crowded
more closely together than when freezing
at the temperature of thirty-two degrees.
1t appears therefore probable that intense
cold acts upon liquids very much like press
ure. And II denser underlying rocks in the
earths crust be more difficult to fuse than su-
perficial ones, in like manner the inferior
portion OF glacier subjected to great press
ure, must be also denser than the surface ice
which has temperature of about 80 deg, and
would therefore require more heat to fuse it.
do not insist that the bottom oil a glacier
where The ice by enormous superimposed
pressure must be greatly reduced from its
normal volume, is equally as cold as ice ex-
posed TO low Arctic temperatures; but that
pressure bestows upon it great capacity OF
conducting cold, and that it may even, for
ought can see to the contrary, have tem-
perature very much belo0 zero. The abnor-
mai density Of ice therefore is its cO-e6ieient
Of expansion.
1t is therefore by the new views OF heat
that the phenomena OF glacier motion must
be explained. The winter motion then OF
the glacier is due to contraction OF the mass
by pressure yielding up heat thereby, which
acting upon the molecular atoms of the ice
mass, becomes an actual energy of notion
But in summer through the agency OF heat,
the compressed mass is no longer able to
maintain ITS winter contracted volume; and
with this additional power swells not only
upgdrd but doonaoard along the plane of
motion; and this accelerated movement con-
tlnues as long as the temperature of the at
mosphere remains above 30 deg.
How beautiful then, do the laws which
control the glaciers motion appear! 1t is
but another proof that the works of nature
are built upon the wisest, and therefore the
simplest plan. We may say then, it is the
sun that not only builds up the glacier, and
that reduces its form, but 1t is he also that
puts the sublime structure in motion.
Falmouth, March, 1868.
T.. Heat" p. 90, and " Glaciers p. 49,.
SKane's Arctic Explorations" vol. p. sos, &