BINOXIDE OF MANGANESE.

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tages over other chalybeates are its ready solubility in water, its palatabletaste, and tlie facility with which it may be mixed with various salinesubstances, without undergoing decomposition. It contains more oxideof iron than the same quantity of sulphate. The dose for an adult isfive or six grains in powder, pill, or solution. It may be exhibited inporter without being detected by the taste. It may be added to thecompound decoction of aloes without suffering decomposition.

Fer'ri Ace'tas.—Acetate of I'ron.

History. —A solution of iron in acetic acid has long been known andused in the arts. It constitutes the iron liquor of the dyer.

Preparation. — In the Dublin Pharmacopoeia acetate of iron isdirected to be prepared by digesting, for three days, one part of carbonateof iron (sesquioxide) in six parts of acetic acid, and then filtering.

Properties.— It is a deep-red liquid, having an acid chalybeate taste.It reddens litmus.

Characteristics. —When heated, it yield acetic acid. Ferrocyanideof potassium strikes a blue colour with it; infusion of galls a purplishblack.

Composition. —It consists of the acetate of the protoxide and acetateof the sesquioxide of iron.

The Physiological Effects and Uses are the same as other ferru-ginous compounds. The Dose is from ten to twenty-five drops, inwater.

Ferri Acetatis Tinctura, Ph . Dubl. (Acetate of potash, twoparts ; sulphate of iron, one part; rectified spirit, 26 parts. Rub togetherthe acetate and sulphate, then dry, and add the spirit. Digest for sevendays, then filter.)—In this process sulphate of potash and acetate of ironare formed: the latter, as well as the excess of the acetate of potash,dissolves in the spirit. It is a claret-coloured tincture. It possesses theusual properties of a ferruginous compound. It is said to be an agreeablechalybeate, and was introduced into the Dublin Pharmacopoeia by Dr.Perceval. The dose is from half a drachm to a drachm.

Tinctura Acetatis Ferri cum Alcohol, Ph . Dubl. (Sulphateof iron; acetate of potash, II sj.; alcohol, Sxxxij. Triturate togetherthe sulphate and acetate, then dry, and when cold add the alcohol.Digest for twenty-four hours.)—The dose is twenty drops to a drachm.

Order 27.— Binoxide of Manganese.

Mangane'sii Bimx’ydum. — Binox'ide of Man!ganese.

History. —Native binoxide of manganese has been long known andused in the manufacture of glass (i magnesia vitriariorum) ; but untilKaim, in 1770, succeeded in extracting a peculiar metal from it, it wasusually regarded as an ore of iron. It is commonly termed native blackor peroxide of manganese, or for brevity manganese.

Natural History. —The oxide of manganese used in chemistry andpharmacy is the native anhydrous binoxide, called by mineralogistspyrolusite. It is found in great abundance in Cornwall , Devonshire,Somersetshire , and Aberdeenshire , from whence most of what is met with