Simple Preparations. 75

venience which cannot, by ajny car?, be wholly a-voidcd. Hence the purer uars, unßrained, arepreferred, for internal ufe, tu the ftrained gums, bythe faculty of Paris. L.

As an additional reafon for this pic. -ence, wemay add, that fome of the gum-refins, puri ! ~.ed inthe common way, by folution in water, expreffion,and ev.iporation, are not fo eafily foluble in aque-ous rnenftrua before, as after, iuch depuration.

CORNU CERVI USTIO.

The Burning of Hartshorn.Burn pieces of Hartfliorn tili they areperfectly white j then rub them to a very finepowder.

R E M A R K.

The pieces of Hörn, generally employed in thisOperation, are thofe left after diftillation. L. Difp.

1746.In the burning of Hartfhorn, a ftrong fire and

the free admiffion of air are neceffary. The pot-ter's furnace was formerly diredted for the fake ofconvenience, but any common furnace, or ftove,will do. If fome lighted charcoal be fpread on thebottom of the grate, and above this the pieces of

the