gun cotton, which is unaffected by moisture, and the explosive force
of which exceeds that of gunpowder.

[1] In M. Verne's book a 'manometer' is the instrument used, of which
very little is known. In a complete list of philosophical instruments
the translator cannot find the name. As he is assured by a first-rate
instrument maker, Chadburn, of Liverpool, that an aneroid can be
constructed to measure any depth, he has thought it best to furnish
the adventurous professor with this more familiar instrument. The
'manometer' is generally known as a pressure gauge.--TRANS.

[2] Ruhmkorff's apparatus consists of a Bunsen pile worked with
bichromate of potash, which makes no smell; an induction coil carries
the electricity generated by the pile into communication with a
lantern of peculiar construction; in this lantern there is a spiral
glass tube from which the air has been excluded, and in which remains
only a residuum of carbonic acid gas or of nitrogen. When the
apparatus is put in action this gas becomes luminous, producing a
white steady light. The pile and coil are placed in a leathern bag
which the traveller carries over his shoulders; the lantern outside
of the bag throws sufficient light into deep darkness; it enables one
to venture without fear of explosions into the midst of the most
inflammable gases, and is not extinguished even in the deepest
waters. M. Ruhmkorff is a learned and most ingenious man of science;
his great discovery is his induction coil, which produces a powerful
stream of electricity. He obtained in 1864 the quinquennial prize of
50,000 franc reserved by the French government for the most ingenious
application of electricity.

The tools comprised two pickaxes, two spades, a silk ropeladder,