·add. ·adj Designating or conforming to either of the scales used by the French chemist Antoine Baume in the graduation of his hydrometers; of or relating to Baume's scales or hydrometers. There are two Baume hydrometers. One, which is used with liquids heavier than water, sinks to 0° in pure water, and to 15° in a 15 per cent salt solution; the other, for liquids lighter than water, sinks to 0° in a 10 per cent salt solution and to 10° in pure water. In both cases the graduation, based on the distance between these fundamental points, is continued along the stem as far as desired.