1. Sixty-three. —⁠Tr.

  2. As Sir Humphry Davy died in 1829, the translator must be pardoned for pointing out here an anachronism, unless we are to assume that the learned Professor’s celebrity dawned in his earliest years. —⁠Tr.

  3. In the cipher, audax is written avdas, and quod and quem, hod and ken. —⁠Tr.

  4. The degrees of temperature are given by Jules Verne according to the centigrade system, for which we will in each case substitute the Fahrenheit measurement. —⁠Tr.

  5. Recherche was sent out in 1835 by Admiral Duperré to learn the fate of the lost expedition of M. de Blosseville in the Lilloise which has never been heard of.

  6. 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. —⁠Tr.

  7. 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.

  8. The name given by Sir Roderick Murchison to a vast series of fossiliferous strata, which lies between the non-fossiliferous slaty schists below and the old red sandstone above. The system is well developed in the region of Shropshire, etc., once inhabited by the Silures under Caractacus, or Caradoc. —⁠Tr.

  9. The name of an Ethiopian tribe who lived in caves and holes. Τρώγλη, a hole, and δύω, to creep into.

  10. One hundred and twenty. —⁠Tr.

  11. These animals belonged to a late geological period, the Pliocene, just before the glacial epoch, and therefore could have no connection with the Carboniferous vegetation. —⁠Tr.

  12. This distance carries the travellers as far as under the Pyrénées if the league measures three miles. —⁠Tr.

  13. Rather of the mammoth and the mastodon. —⁠Tr.

  14. The glyptodon and armadillo are mammalian; the tortoise is a chelonian, a reptile, distinct classes of the animal kingdom; therefore the latter cannot be a representative of the former. —⁠Tr.

  15. The facial angle is formed by two lines, one touching the brow and the front teeth, the other from the orifice of the ear to the lower line of the nostrils. The greater this angle, the higher intelligence denoted by the formation of the skull. Prognathism is that projection of the jawbones which sharpens or lessens this angle.

  16. “The shepherd of gigantic herds, and huger still himself.”