74

Simple Preparations.

AMMONIACI PURIFICATIO.The Purification of Ammoniacüm.

Böil Gum-Ammoniacum, if it appears im-pure, in water tili it foftens, and prefs itthrough an hempen cloth ; then fet it by, thatthe refinous part may fubfide. Evaporate thewater ; and, towards the end of the infpifla-tion, reftore the refinous part, and mix itwith the gummy.

In the fame manner are purified Afa Festi-da an 1 fuch like Gum-refins.

You may alfo purify any gum, which meltsean!y ; fuch as Galbanum, by putting it intoan ox-bladder, and holding it in boiling wa-ter tili it is fo foft that it can be feparated fromits impurities by preffing through an hempencloth.

R Z M A R K.

In the ftraining of all the Gums, care fhould belaken that the heat be neither too great nor too longcontinued, otherwife a confiderabie portion of theirmore aclive volatile matter will be loft, — an incon-

venience