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"
"You mean, then," I cried in amazement, "that he should accompany us?"
"To the interior of the earth, yes," replied my uncle. "Why not?"
There were yet forty-eight hours to elapse before we made our final
start. To my great regret, our whole time was taken up in making
preparations for our journey. All our industry and ability were devoted
to packing every object in the most advantageous manner--the instruments
on one side, the arms on the other, the tools here and the provisions
there. There were, in fact, four distinct groups.
The instruments were of course of the best manufacture:
1. A centigrade thermometer of Eigel, counting up to 150 degrees, which
to me did not appear half enough--or too much. Too hot by half, if the
degree of heat was to ascend so high--in which case we should certainly
be cooked--not enough, if we wanted to ascertain the exact temperature
of springs or metal in a state of fusion.
2. A manometer worked by compressed air, an instrument used to ascertain
the upper atmospheric pressure on the level of the ocean. Perhaps a
common barometer would not have done as well, the atmospheric pressure
being likely to increase in proportion as we descended below the surface
of the earth.
3. A first-class chronometer made by Boissonnas, of Geneva, set at the
meridian of Hamburg, from which Germans calculate, as the English do
from Greenwich, and the French from Paris.
4. Two compasses, one for horizontal guidance, the other to ascertain
the dip.
5. A night glass.
6. Two Ruhmkorff coils, which, by means of a current of electricity,
would ensure us a very excellent, easily carried, and certain means of
obtaining light.
7. A voltaic battery on the newest principle.[1]
[1] Thermometer (thermos, and metron, measure); an instrument for
measuring the temperature of the air.--Manometer (manos,and metron,
measure); an instrument to show the density or rarity of
gases.--Chronometer (chronos. time, and metros, measure) a time
measurer, or superior watcg--Ruhmkorff's coil, an instrument for
producing currents of induced electricity of great intensity. It
consists of a coil of copper wire, insulated by being covered with silk,
surrounded by another coil of fine wire, also insulated, in which a
momentary current is induced when a current is passed through the inner
coil from a voltaic battery. When the apparatus is in action, the gas
becomes luminous, and produces a white and continued light. The battery
and wire are carried in a leather bag, which the traveler fastens by a
strap to his shoulders. The lantern is in front, and enables the
benighted wanderer to see in the most profound obscurity. He may venture
without fear of explosion into the midst of the most inflammable gases,
and the lantern will burn beneath the deepest waters. H. D. Ruhmkorff,
an able and learned chemist, discovered the induction coil.
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