Baumé scale

:  either of two hydrometer scales that indicate specific gravity in arbitrarily defined but constant degrees:a:  one for liquids lighter than water on which specific gravity S at 60°F (15.6°C) is related to the Baumé reading noun in degrees by S = 140 ÷ (130 + noun)b:  one for liquids heavier than water on which specific gravity S at 60°F (15.6°C) is related to the Baumé reading noun in degrees by S = 145 ÷ (145 − noun)