An aneroid barometer, to indicate extreme pressures of the atmosphere. 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.

2. 无液气压计，用于指示大气的极端压力。普通气压计无法满足该目的，因为在我们下降过程中压力会增加到水银气压计 [1] 无法记录的点。