Lot 307: A Pair of Vintage A. Gallenkamp & Co. Ltd. Twaddell No. 2 Glass Hydrometers

A pair of scientific hydrometers manufactured by A. Gallenkamp & Co. Ltd. of London. These instruments are constructed from blown glass and utilize the Twaddell scale for measuring the specific gravity of liquids. Each hydrometer features a long cylindrical stem with an internal paper scale and a weighted bulb at the base. One bulb contains dark metallic shot, while the other contains a yellowish-green weighting substance. The paper scales are printed with the following inscriptions: TWADDLES No 2 . A. GALLENKAMP & CO. LTD. LONDON TEMP. 60. and MADE IN ENGLAND. The scale range is graduated with the number 48 visible at the upper limit. The notation TEMP. 60 indicates the instruments are calibrated for use at a standard temperature of 60 degrees Fahrenheit.