Sikes Hydrometer, Complete With Original Weights And Thermometer. This complete and original Sikes Hydrometer set is signed with a serial number 2666 and includes an ivory thermometer, float, 10 weights that are numbered 2666 and Mahogany case. This is a brass instrument set used to determine the strength of spirits providing an accurate method of determining alcohol proof, strength, and percentages. Sikes's hydrometer was enshrined in legislation in 1816 with the Sikes Hydrometer Act and remained the legal standard until 1907. The is box 21 X 9.5 cm (8 ΒΌ X 4 inch). The hydrometer was retailed by A Reynolds & Co in Leeds.