A boxed hydrometer (serial no.16234) with all parts, includes thermometer, ten weights and float, in fitted case.

Top plate marked: "Sikes' Hydrometer, Riddels Limited. Belfast."

In 1802, the English Board of Excise held a competition to find the best instrument for revenue purposes - the winning design was that of Bartholomew Sikes, a peripatetic London employee of the excise commissioners. Sikes's hydrometer was enshrined in legislation in 1816 with the Sikes Hydrometer Act and remained the legal standard until 1907.

The Sikes hydrometer was used to determine the strength of spirits for the distiller, victualler and tax collector alike, and worts both before and after fermentation for the brewer, providing an accurate method of determining Alcohol proof, strength, percentages and duties thereof.