Beaume Hydrometer

The Baumé hydrometer, named after the French chemist Antoine Baumé, is calibrated to measure specific gravity on evenly spaced scales. This particular one is for liquids heavier than water and printmakers use it for measuring the strength of the Ferric Chloride they are using for etching.

The scale is based on the principle that the density of a liquid is related to its concentration of solutes, and it measures the specific gravity of a liquid relative to the density of water, rather than the concentration of a solution per se.

23cm long