New-York tribune., 1901-11-10
THE EARTH'S HOT INTERIOR
CAN 1T BE UTILIZED AS A SOURCE
OF POWER?

comes from burning coal Apd inasmuch as the
unmined supply of that material has its limita-
tions and is likely to be used up inside OF a
couple of centuries, if not sooner, engineers ana
philosophers have begun to cast ABOUT for other
resources The substitutes for coal which are
generally suggested are falling water the "lhu'
sunshine and the waves and tides But Fro-
fessor r c. MendenhaH in "Cassier's Maga-
zine makes a somewhat novel addition 10 the
list Referring 10 the interior heat of the earth,
he says that it lis worthy of most SERIOUS con-
sfderation a possible and reasonaDe source
of power. It's Importance will be greatly en-
hanced when We able to transform neat
directly into electricity large scale ana
with economy avoiding the great waste when
necessarily accompanies the use OF the steam en-
gine; and this must soon come about
| The earth is a globe nearly 5000 miles in
diameter and except for thin shell, is prob
ably hotter than any furnace yet devised oS
human skill. Estimates differ as to the thick
ness of this crust. Temperature increases WIN
descent in mines and oil wells, at an average
rate of one degree Fahrenheit for every fifty or
sixty feet. Assuming that the mean I0r the
earths surface is something like 90 degrees
above zero, the boiling point of water (212 de-
grees) would be reached at depth of about
| s 600 feet And it is believed that between
thirty and fifty miles down the heat is su1iciehe
| to melt the hardest known substances-clay'
lime carbon and the like 1t would probably
not be wide of the mark to say that az TINS
distance temperatures of 1900 and 6.ooo degrees
| exist.
| The old notion that the interior OF the
earth was molten ard the phenomena OF VOL
| canoes tended to strengthen that belief Mod
ern writer's. however incline to the theory or
| potential Ilasticity.' That is TO say, they
| think that the heat there is adequate 10 melt
the most refractory materials. but that netting
does not actually take place, owing to the pres
sure of superintendent weight
! 4 moments reflection Will satisfy one that II
this source Of energy should ever become avail
able il would vastly transcend in value wind
power water power, power and tide power
Even the coal deposits of the earth. consumed
and unconsumed, would be inconsiderable IN
comparison Were the internal heat drawn off
by artificial means-the conversion into other
forms OF energy for mans use-the cooling Of
the globe. which is already going on, would De
accelerated and the earth would be reduced 10
! the cold dead condition Of the moon a little
sooner than otherwise. Thus The very existence
OF the human race might possibly be abbrevi-
ated few thousand years by climatic changes
Still if the great heat reservoir here under con-
sideration were tapped in u satisfactory
manner. it would be practically inexhaustible
bank account To draw upon
| Professor MendenhaH outlines plan for
utilizing the earth's heat beyond suggestion
that il might be converted directly into eIec-
trcity without the intermediate use Of steam
1 Their, is much to commend this idea. Il it IS
necessary to go down 5000 feet in order to
make water boil. il would be necessary TO 50
2OtyO more To generate steam at a useful pres
sure say 40 or -uO pounds 70 the inch. To He
I sure werv some more volatile substance than
water employed produce the motive Vapor.
/ a lower temperature would suffice This Is the
principle Of a motor in Germany which just
now threatens to work a revolution in power
generation 1t takes the exhaust of 4 condeEs-
ing steam engine. at temperature of about
100 degrees. vaForiZes herewith some sulphur
! doxiie and thus gets more than third
much power as the principal engine develops.
This heat would otherwise be wasted sui
phur dioxide engine might be run successfully.
/ SO far as temperature conditions alone are con-
| cerned at depth of mile, which has more
than once been attained by oil wells.
| The principle of the Jhermo-electriC couple IS
very simple. When change of temperature
occurs at the junction of two slips of diSSItiiiar
metals an electric current is excited in them.
| Many inventors have tried to turn that phe-
nomenon to account diamond built UP hollow
| cylinder of alternate layers of tin and an
| alloy containing antimony. and heated the in
terror with Il gas flame formed around a per-
| forated eartheaware tube Harry BarrinSer