Microscope Museum

Collection of antique microscopes and other scientific instruments

Sike’s hydrometer by J. Long (late 19^th century to the early 20^th century)

Sike’s hydrometer, complete with a thermometer, dated from the late 19^th century to the early 20^th century. The wooden box containing the instrument is labelled ‘SIKE’S HYDROMETER BY J. LONG, 43 EASTCHEAP, LONDON’. The wooden box is also engraved with the serial number 26187, as well as all the weights and thermometer. The Sike’s hydrometer is used to determine the density of a fluid, by floating the hydrometer in the fluid and noting its buoyancy from its scale. A set of weights that attach to the hydrometer is used to adjust the range of the instrument. The thermometer is used to determine the temperature at which the measurement is being made. This type of hydrometer was originally invented by Bartholomew Sikes in the late 18^th century, with the objective to measure the alcoholic content of a liquid. The success of the device caused his name to be immortalised in an Act of the UK’s Parliament (the Sikes' Hydrometer Act 1816), and the Sike’s hydrometer was the standard approach in the UK to measure the alcohol proof of spirits from 1816 until 1980. Joseph Long was a mathematical, optical and hydrometer instrument maker. The company J. Long traded at 20 Little Tower St. (1821 - 1884) and 43 East Cheap (1885 - 1936), both in London, England.

LAST EDITED: 18.09.2021