thalpotasimeter

from The Century Dictionary.

• noun An apparatus for observing, measuring, or recording the intensity of high heats: a form of pyrometer for high heats.
• noun Specifically An apparatus of the kind which uses the tension of a vapor as a means of observing the heat, as that of the vapor of ether for lower ranges, and that of the vapor of mercury for greater. The vapor-tension moves a gage-needle over a dial, or a recording-lever may be moved across a moving disk or band of paper.