Lot 308: A Pair of Antique Twaddell Pattern Glass Hydrometers

A pair of antique Twaddell pattern glass hydrometers, designed for measuring the specific gravity of liquids denser than water. These instruments are constructed from hand-blown glass, featuring a narrow stem containing a printed paper scale, a large buoyancy bulb, and a smaller terminal bulb at the base containing dark metallic ballast. The first hydrometer is marked with the inscription Twaddell’s Hydrometer Tp. 60º F. № 4, with a scale graduated from 74 to 102. The second hydrometer is marked Twaddell’s Hydrometer № 5 Tp. 60º Fahrht. made in Germany, with a scale graduated from 102 to 138. Both instruments are calibrated for a reference temperature of 60 degrees Fahrenheit. These types of hydrometers were traditionally used in various industrial processes, including chemical production, tanning, and dyeing.