But my uncle seemed to believe in his arsenal as in his instruments, and more especially in a considerable quantity of 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.