DECANT A′TION

The operation of pouring or drawing off the clear portion of a liquid from the impurities or gro er matter that has subsided. It is commonly performed, either by gently inclining the ve el, or by the use of a syphon or pump. In the laboratory it is much resorted to in the purification of precipitates, or other similar operations, where repeated edulcoration or washing is required, for which purpose it is preferable to filtration, from being le troublesome and more economical. In these cases, after a sufficient time having been allowed for the subsidence of the precipitate or powder, or for the clearing of the supernatant fluid, the latter is decanted, and its place supplied by a fresh portion of water, which, after sufficient agitation, is similarly treated, and the whole operation repeated as often as nece ary.