hypsometer

The readings of the hypsometer gave practically the same result day after day; the ascent we were looking for failed to appear.
The South Pole, Volumes 1 and 2|Roald Amundsen
At the same time, inside the tent we got the water to boiling and took a reading with the hypsometer.
Inca Land|Hiram Bingham
Mertz boiled the hypsometer when necessary to ascertain our elevation above sea-level.
The Home of the Blizzard|Douglas Mawson
The hypsometer is only an instrument for determining the boiling-point, which gives one the height above the sea.
The South Pole, Volumes 1 and 2|Roald Amundsen

I took the observation for longitude and latitude, found the height by hypsometer, and took some photographs.
The South Pole, Volumes 1 and 2|Roald Amundsen

British Dictionary definitions for hypsometer

hypsometer

/ (hɪpˈsɒmɪtə) /

noun

an instrument for measuring altitudes by determining the boiling point of water at a given altitude

any instrument used to calculate the heights of trees by triangulation

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for hypsometer

hypsometer

[ hĭp-sŏm′ĭ-tər ]

An instrument used to determine land elevation by observing the atmospheric pressure as measured by the change in the boiling point of a liquid, usually water. Liquids boil at progressively lower temperatures as the atmospheric pressure decreases, and since atmospheric pressure decreases with altitude, the temperature at which the liquid boils is an indicator of the atmospheric pressure at that location and hence of the location's altitude.