An ordinary barometer would not have answered the purpose, as the pressure would increase during our descent to a point which the mercurial barometer [1] would not register.
3.

A chronometer, made by Boissonnas, jun., of Geneva, accurately set to the meridian of Hamburg.
4.

Two compasses, viz., a common compass and a dipping needle.
5.

A night glass.
6.

Two of Ruhmkorff's apparatus, which, by means of an electric current, supplied a safe and handy portable light [2] The arms consisted of two of Purdy's rifles and two brace of pistols.
But what did we want arms for?
We had neither savages nor wild beasts to fear, I supposed.