The new North-west. [volume] (Deer Lodge, Mont.) 1869-1897, 1881-07-29
The lnrerior'of,ne Earth.
Belgraria.

~ IF y
That the interior If the earth is the seat
of intense heat is familiar truth. Vo'canic
phenomena give us ocular demonstration Of
IL. Mining experiences, moreover, have fur
nlsI,~d us with almost a uniform rate at
which the heat increases. and this ID general
" computed to be about II Fahrenheit for
every fifiy-fve feet Of descent. But mining
experiences are necessarily very limited.
The deepest mine In England, that pf the
Rosebiidge Colliery. near Wigan, takes US
down only 2,445 feet, aud to temperature
not much exceeding 90' Fahrenheit. 1t Is
hot enough to make the work exceedingly
trying to the miners, but that Is all. This,
however, is ESQ to spesk) scarcely traverslng
the earh's epidermis. But II We may as
snne uniform Increase In heat In descend
Ing, the temperature At depth Of hffy miles
may be expressed In figures At 4,s0o' Fahren-
heit. In other words, al less than ~ eighth
az the distance which lies between the cir
cumference of the eath and It's centre, the
heat would bs about twenty-five tunes the
heat of boiling wate. At the sea-level. Pro-
portionste figures might, Of course. express the
heat a still greater depths, but Agures fail 70
convey any idea to The mind Of that which
must necessarily transcend all imagination.'
Suffice 1t to say, that In descending series
we must eventually come to heat % great
that no suhsi ance with which we are &C.
euainted could, under any condition which
We can imagine, exist In 1t In either solid or
fiuid firm. And we conclude, therefore,
that II the earth's smf,ce be not itself In .
gaseous condition salld there is reason to
think that II may not be SOY there must be .
gaseous zone somewhere between asolid CEN
tire aud . solid circumference. We can
measure The power Of pressure upon the sur
face. but In the neither depths Its power Is In
part open TO conjectnrs, nor can we say how
soon we may reach debsiable zone, at
which the expansiveness Of heat may over
come the compressive force of eravitation.
| Nor, again, could we venture to expect 70
Rnsi thst snne itself It uniform depth.
| Here and there Il seems to approach the sur
lace. The volcano Is natures ssfety-vaive,
and the cavernous rumble VI the earthquake
warns us that there are imprisoned gases be.
meath our Feet which pressure bnt imperfect.
" prevents from escaping. Upon Other
ground, also, It Is quite evident that our ex
perience, limited y It Is TO the surface Of thu
earth. may tend to mislrad US In regard u
wha. lies ben~aih the surface; for II prrssurs
increased uniformly with depth, the average
density Of the earth would be much greater
than what npon astronomical data We know
Il 10 BE-. The earth, IS whole, Is about fiv'
and half times Is heavy IS Il would be II :
we're entirely composed Of water; or. tech
nically expressed, the density Of water i
one, and the mean density Of the globe i
1--WE and half. But five and half u onl!
about double the density u rock matte
upon the su,face; whereas, II nothing b..
steadily increasing pressure Is suppnsed.
would vastly exceed this. There Is, there
i fore. only one possible explanation. H~at
intense heat, somewhere or other, overcome
| pressure aud converts everything into gas
and, II 1t were in our power TO try expert
ments. and TO feed the subterTanean cfncibl
with the most iniraei able alsl,sf sfances---ssbes
tps, tire-proof saf's, or what we will--sl
would there share the same fate-instaIl
eyaiiescence.