Webster’s Revised Unabridged Dictionary · 1913
Elatrometer
El′a·trom′e·ter (ĕl′ȧ·trŏm′ē·tẽr), n. [Gr. ἐλατήρ a driver + -meter.] (Physics) An instrument for measuring the degree of rarefaction of air contained in the receiver of an air pump. [Spelt also elaterometer.]