Abbreviation for British Association. It is prefixed to standards fixed by the committee of the British Association for the Advancement of Science. Thus the B. A. ohm means the British Association ohm, a measure of resistance which is equal to the resistance of a column of mercury 104.9 centimeters long and one square millimeter area [...]

(a) Abbreviation for Baumé, a hydrometer scale. (See Baumé.) Thus 10º B. means “ten degrees Baumé.” (b) Symbol for the coefficient of induced magnetization, or the number of lines per square centimeter induced in a magnetic circuit or in any specified part of it.