The Collaborative International Dictionary
Thermobarometer
Thermobarometer \Ther`mo*ba*rom"e*ter\, n. [Thermo- + barometer.]
(Physics) An instrument for determining altitudes by the boiling point of water.
A siphon barometer adapted to be used also as a thermometer.
Wiktionary
thermobarometer
n. 1 (context obsolete physics English) An instrument that measured altitudes via the boiling point of water 2 (context geology English) A mineral used to estimate temperature and pressure in the rocks during its formation