PART III.

Metallic Preparations. — Iron".

521

By the degree of heat employed, the sulphuric acid of thesulphate is partly driven off in a highly concentrated state,and partly decomposed, sulphurous acid being disengaged,and the oxide, which is the base of the sulphate, becomesmore highly oxidized.

The residue is the red oxide of iron, combined with a por-tion of the red sulphate, which renders it deliquescent; andwhich should therefore be separated by washing, as directedby the Dublin College.

According to Proust, the red oxide at the highest degree ofoxidizement consists of 48 parts of oxygen and 52 of iron.

Medical properties and uses. —This preparation is possessedof the same medicinal properties as the other preparations :but it is very rarely used, except as a pharmaceutical agent.

Officinal preparation. Murias Ammonia et Ferri. E. D.

EERRUM TARTARIZATUM. Lond. TartarizedIron.

" Take of iron, a pound ; supertartrate of potash, in pow-der, two pounds; water, a pint. Rub them together, andexpose the mixture in an open glass vessel to the action of theair for eight days ; then dry it in a sand-bath, and reduce itto a very fine powder. To this powder add a pint of water,and put it aside for eight days; then dry it, and reduce it topowder."

Tartras Potass^e et Ferri. Edin. 1 Tartrate of Potashand Iron.

"Take of purified filings of iron, one part ; supertartrateof potash powdered, tino parts ,■ water, one part. Rub themtogether and expose them to the air in a shallow earthen ves-sel for fifteen days, stirring the mass daily with a spatula, andkeeping it moist by frequent additions of water. Then boilthe whole for a short time in four times its weight of water,and pour off the solution from the other faeces. Evaporatethe solution to dryness in a water bath, and having rub-bed the mass into powder, preserve it in a well-stoppedbottle."

Tartarum Fejiri.* Dub. Tartar of Iron.

" Take of carbonate of iron, half an ounce ; crystals of tar-tar in very fine powder, an ounce; distilled water, a pint.Let them be put into a glass vessel, then boiled for an hourover a slow fire, and the liquor filtered through paper; whenthis is cold, filter it again, and evaporate it until a pellicleappears on the surface: the liquor, as it cools, will concrete

1 Tartrate fie Fer et de Potasie (F.) Eissenweinstein (/.) Tanrato di Potassa ediOssido di Ferro (G.)

* It is remarkable that both the London and Dublin Colleges should err in givinga name to this triple salt so dissonant to the principles of the reformed nomenclatureof their pharmacopoeias.