'actinic balance' definitions:

Definition of 'actinic balance'

From: GCIDE

Bolometer \Bo*lom"e*ter\, n. [Gr. ? a stroke, ray + -meter.] (Physics) An instrument for measuring minute quantities of radiant heat, especially in different parts of the spectrum; -- called also actinic balance, thermic balance. --S. P. Langley. [1913 Webster]