FER

aiu

ur what is perhaps more eligible, in the form of an electuary. TheMahometan practitioners are in the habit of prescribing them, in conjunc-tion with ginger, and cummin seeds, in cases requiring tonics. Dose,grs. v to 3ss. Impurities. Iron filings should be carefully purified bythe application of the magnet, since those obtained from the workshop,are generally mix-, d with opper and other metals. For pharmaceuti-cal purposes, iron wire should he preferred, as being the most pure,since the softest iron only can be drawn, and Mr. Phillips has shewn us,in his experiments upon the " Ferrum Tartarizatnm" that soft iron ismore easily acted upon by Tartar.

FERRl SULPHAS. L. Sulphas Ferri. E.D.

Ferrum Vitriolatum. P.L 1787. Sal Martis. P.L. 1745.

Sal, seu Vitriolatum Martis. P.L. 1720.

Sulphate of Iron, formerly Green Vitriol.

Qualities. Form, crystals, which are rhomboidal prisms, transparent,and of a fine green colour ; when exposed to the air tbey effloresce, andat the same time become covered with a yellow powder, owing to the at-traction of oxygen ; when exposed to heat, they undergo watery fusion,and at a higher temperature, the acid is driven off and the peroxide ofiron alone remains, which in commerce is known by the name of Colco-thar Chemical Composition. According to Dr. Thomson, it consistsof 27 7 of sulphuric acid, 28'3 of protoxide of iron, and 45 of water ;3 parts, however, of this water, exist in combination with the oxide ofiron. The Medicinal Dynameter will shew the proportion of protoxidein any given weight of this salt Solubility. It is soluble in two partsof water at 60°, and three-fourths at 212°. The solution reddens vegeta-ble blues. It is insoluble in alcohol ; when however the iron is fartheroxidized, it becomes soluble in that menstruum.* Incompatible Sub.stances. Every salt whose base forms an insoluble compound with sul.phuric acid ; the earths, the alkalies, and their carbonates ; borate of soda;nitrate of potass, muriate of ammonia; tartrate of potass, and soda; ace-tate of ammonia ; nitrate of silver ; sub-acetate and acetate of lead ; andSoaps. Whether the medicinal virtues of a sail of iron are injured bycombination with astringent vegetable matter, seems to admit of doubt.Such substances have been usually ranked amonst the incompatibles, but Iam disposed to think without sufficient grounds, for I have frequentlywitnessed the salutary effects of iron when exhibited in this questiomblestate of combination—may not the absorbents be more disposed to take upiron, when combined with vegetitde matter, than wheu it is presented in amore purely mineral form ?t Medicinal Uses. Tonic, astringent,emmenagogue, and anthelmintic : in large doses, it occasions griping in the

* This fact furnishes the Pharmaceutic Chemist with an easy and effectual mode ofcleansing the green crystals from the yellow peroxide which forms upon their surface,viz. by washing them in spirit.

+ By a parity of reasoning, VIr. Carmichael is led to prefer the phosphate of iron toany other preparation of that metal, in cancer, because he thinks iron, combined withan animal acid, enters the system in greater quantity, and unites more intimately withthe juices.

Aromatic Lozeivces of Steel. These consist of sulphate of iroa, with a small■proportion of the tincture of Cantharkles

m