Mathiesen, Hans-Lorenz: Eine hydrostatische Waage. In DrechselMagazin 32 (2015), 22-23

Hydrostatic Balance on the model of 's Gravesande

Branch of study: hydrostatics
Inventor: Willem Jacob 'sGravesande, 1737

This device is used to determine the mass density of liquids. To do so the cups under the scale pans are filled with two different liquids. Attached to the bottom side of the scale cups are weights which then are submerged into the respective liquids. A difference in the mass density would results into one side being lifted up more due to bouyancy. This can be levelled again by adding weights onto the top side of the scale's pans. The added weight is then used to calculate the difference in the density of the liquids.

The instrument was described for example in 'sGravesandes Mathematical elements of natural philosophy, confirm'd by experiments (1737) or An introduction to Sir Isaac Newton's philosophy (J.T. Desaguilers, Trans.), London. The instrument's original is on display in the Museum Boerhave in Leiden, Netherlands  Museum Boerhaave Leiden