is the freeing of any fluid from its heterogeneous matter or feculence. It is of three kinds; 1. Decantation; which is performed by letting the liquor to be depurated stand for some time in a pretty deep vessel, till the gross sediment has fallen to the bottom; after which the clear fluid is poured off. 2. Despumation; which is performed by means of the whites of eggs, or other viscid matter, and is also called CLARIFICATION. 3. Filtration; which is effected by passing the fluid through cloth or porous paper.