[mod. f. Gr. ἀραιός thin + μέτρον measure: see -METER. App. through F. aréomètre: whence the prevalent spelling, as if from AREA, or AREO-, of Mars.] An instrument, consisting of a graduated glass tube terminating in a loaded bulb, for measuring the specific gravity of fluids; a hydrometer. Hence: Aræometric a. [see -IC], of or pertaining to aræometry. Aræometrical a. = prec. Aræometry [Gr. -μετρία measurement], the art or science of estimating the specific gravity of fluids by means of an aræometer.
1706. Phillips, Areometer.
1730. Desaguliers, in Phil. Trans., XXXVI. 277. The Hydrometer, by some called Areometer.
1731. Bailey, Aræometer.
1751. Chambers, Cycl., The Aræometer or waterpoise is usually made of glass.
1876. Ure, Dict. Arts, I. 207. The areometer of Baumé is used in France.
1871. B. Stewart, Heat, § 54. The areometric method, or that of weighing a solid in the liquid.
1847. Craig, Areometrical.
1778. Phil. Trans., LXVIII. 419. An Essay, on Pyrometry and Areometry.
1819. Rees’ Cycl., II. s.v. Aremometer, Invented by Wolfius in 1708, and first published in his ‘Areometry.’
