Black flux

Flux Flux (fl[u^]ks), n. [L. fluxus, fr. fluere, fluxum, to flow: cf.F. flux. See {Fluent}, and cf. 1st & 2d {Floss}, {Flush}, n., 6.] 1. The act of flowing; a continuous moving on or passing by, as of a flowing stream; constant succession; change. [1913 Webster]

By the perpetual flux of the liquids, a great part of them is thrown out of the body. --Arbuthnot. [1913 Webster]

Her image has escaped the flux of things, And that same infant beauty that she wore Is fixed upon her now forevermore. --Trench. [1913 Webster]

Languages, like our bodies, are in a continual flux. --Felton. [1913 Webster]

2. The setting in of the tide toward the shore, -- the ebb being called the {reflux}. [1913 Webster]

3. The state of being liquid through heat; fusion. [1913 Webster]

4. (Chem. & Metal.) Any substance or mixture used to promote the fusion of metals or minerals, as alkalies, borax, lime, fluorite. [1913 Webster]

Note: {White flux} is the residuum of the combustion of a mixture of equal parts of niter and tartar. It consists chiefly of the carbonate of potassium, and is white. -- {Black flux} is the ressiduum of the combustion of one part of niter and two of tartar, and consists essentially of a mixture of potassium carbonate and charcoal. [1913 Webster]

5. (Med.) (a) A fluid discharge from the bowels or other part; especially, an excessive and morbid discharge; as, the bloody flux or dysentery. See {Bloody flux}. (b) The matter thus discharged. [1913 Webster]

6. (Physics) The quantity of a fluid that crosses a unit area of a given surface in a unit of time. [1913 Webster]