'Hypsometer' definitions:

Definition of 'hypsometer'

noun

An altimeter that uses the boiling point of water to determine land elevation

From: GCIDE

Hypsometer \Hyp*som"e*ter\, n. [Gr. ? height + -meter.] (Physics) An instrument for measuring heights by observation of barometric pressure; esp., one for determining heights by ascertaining the boiling point of water. It consists of a vessel for water, with a lamp for heating it, and an inclosed thermometer for showing the temperature of ebullition. Hypsometric