The Lambertville record. [volume] (Lambertville, N.J.) 1872-1968, 1881-11-02
MISCELLANY.
HEIN7BRIoR or THE EARTH.

That the interior of the earth is the seat of
intense heat is familiar truth. Volcanic
phenomenon give us ocular demonstration of
it. Mining experiences, moreover, have fur
nished us with an almost uniform rate at
which heat increases, and this is generally
computed to be about one degree Fahrenheit
for every 55 feet descent. But mining ex-
periences are necessarily very limited. The
deepest mine in England, that of the Rose
bridge co'iery, near Wigan, takes us down
only 2445 and in temperature not much ex-
ceeding 90 degrees Fahrenheit. 1t Is
enough TO make the work exceedingly trying
to the miners, but that is all. That however
is $50 to speak, scarcely tiaversing the earth's
epidermis. But if we may assume a uniform
increase of heat in descending, the tempera-
ture at depth of fifty miles may be expressed
in figures as 1890 degrees Fahrenheit. In
other words, at less than an eighth of the dis
lance which lies between the circumference of
the earth and its centre, the heat would be
about % times the heat of boiling water at
of course, express the heat at greater depths
still, but figures fail to convey any idea to the
mind Of that which must necessarily trans
cend all imagination. Suffice to say, that in
descending series we must come to a heat SO
great that no substance with which we are
acqua inted could, under any conditions which
we can imagine, exist in it in either solid or
that il the earth's centre be not itself in a
gaseous condition land there is reason to think
that 1t may not be SOY there must be gaseous
zone somewhere between solid centre and
solid circumference 'Baciiis descensus AgerssG''
is proverbially treated as truism. But if
the classic authors are to be our guides, and if
in the centre of our planet Acherotian shades
and Elysian fields are to be localized, there
will be found practical difficulties of access
which we'll might discourage even so sub
stantial parsonage as ghost. Nor can the
all powerful Imagination accomplish the de-
scent with any approach to ease. The dis
lance we may suppose to be nearly 1890 miles !;
but along line of this length connecting the
surface of the earth with its centre, we may
safely assume that conditions would vary
greatly, and (since heat and pressure have to
be balance one against the other) probably by
no means uniformly. We can measure the
power of pressure upon the surface but in the
neither depths it power is in part open to con-
lecture, nor can we say how soon we may
reach debatahle zone, at which the expan-
siveness of heat may overcome the compress
sive force of gravitation. Nor, again, could
we venture to expect to find the zone itself
always at uniform depth. Here and there
it seems to approach the surface. The vol
cano is natures safsty-valve, and the cavern
GUS rumble of the earthquake warns us that
there are imprisoned gases beneath our feet,
which pressure but imperfectly prevents from
escaping. Upon other ground, also. 1t is quite
evident that our experience, limited as it is to
the surface of the earth, may tend to mislead
us in regard to what lies beneath the surface;
for If pressure increased uniformly with depth
the average density Of the earth would be
greater than what upon astronomical data, we
know 1t to be. The earth, as a WHOLE is about
five and a half times as heavy as it would be
if it were entirely composed of water or,
technically expressed the density of water Is
one, and the mean density of the globe is five
and half. But five and half is only about
double the density of rock matter upon the
surface whereas, If nothing but steadily in
creasing pressure be supposed, 1t would vast
ly exceed this. There is, therefore, only one
possible explanation. Heat, intense heat,
somewhere or other, overcomcs pressure and
converts everything into gas aud If it were
r
the subtertanean crucible with the most in
tractable substance asbestos, fire proof safes
or what we will-all would there share the
same fate--instant evanescence. BelgrGoiG.