Hydrometer
Bouvier's Law Dictionary and Concise Encyclopedia · John Bouvier; revised by Francis Rawle · 1914
Bouvier's Law Dictionary and Concise Encyclopedia
An instrument for measuring the density of fiuids: being Immersed in fiuids, as in water, brine, beer, brandy, etc., it determines the proportion of their density, or their specific gravity, and thence their quality.
See Act of Congr. Jan. 12, 1825, 3 Story, Laws 1976.