The ebullioscope can also be used to determine the molecular weights of substances by measuring the extent to which they change the boiling point of a solvent. 

Invented in the 1830s, the ebullioscope became an important instrument for chemistry and physics. Its original use was to determine the proof (alcohol content) of wine and spirits. It quickly became a staple in chemistry labs and a pain in the ass lab assignment for chemistry students calculating boiling points and molecular weights.