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FERRUM.— IRON.

A substance of an earthy appearance andbrownish-yellow colour, giving a yellowpowder.

C.

Umbra. — Umber.Synonime :— Terre d'Ombre, Fu.Bruns. ; Guibourt.

A brown variety of the preceding.

3. IMPURE.

Chalcitis.

Synonimes : — Chalcitis, Colcothar natif,Fr.

Gall.

A mixture of tritoxide and of sulphate ofiron, and almost always containing sulphateof copper. It is produced by the spontane-ous decomposition of the sulphuret of ironin the earth.

PREPARATION OF THE NATURAL OXIDE.

R. Chalcitis, any quantity.

Calcine it for some time in an earthenvessel, and then reduce it to powder.(Palat.)R. Red Ocre, any quantity.

Having pulverized and levigated it, mixit with a great quantity of water, and sepa-rate the subtle powder by setting aside thedecanted turbid liquor. (Herbip.)

Palat. ; and Sard, direct the levigatedpowder to be made into pastilles or trochiscs.

Palat. directs the same process for theeagle-stone.

PREPARED ACCORDING TO VARIOUSFORMULA.

Edinb. ; Dubl. ; Amer. ; Amst. ; Ant. :Batav. ; Bruns. ; Hisp. ; Gall.Fenn. ; Fuld. ; Lipp. ; Palat. ; Sard.Suec ; Wirtem. ; Herbip. ; CoxeSpielmann ; Van Mons.

I. Colcothar Vilrioli, Sulphas Ferri Calci-natum, Ferrum vitriolatum ustum, TerraVitrioli dulcís, Crocus Martis vitriolatusseu adstringens, Chalcitis, Caput morhmmVitrioli.

Oxydum Ferri Rubrum. (Edinb.)

R. Dried Sulphate of Iron,

any quantity.Expose it to a violent heat till itis converted to a red-coloured sub-stance.

Ferri Oxydum Rubrum. (Dubl.)R. Sulphate of Iron, any quantity.Expose it to heat till the water ofcrystallization is dissipated ; then ex-pose it to a more violent heat till nomore acid vapour is disengaged.Wash the red oxide which is formed,with water, till this ceases to indicate,by the test of litmus, the presence ofany acid, and then dry it on bibulouspaper.

R. Sulphate of Iron, any quantity.

Calcine it in a crucible placed in a strong

fire, till it is converted into a deep-red

mass ; wash well and preserve it. (Amer. ;

Amst.; Ant.; Batav.; Bruns.; Hisp.;

Gall.; Ferr. ; Fuld.; Lipp.; Sard.;

Suec. ; Wirtem. ; Herbip. ; Coxe ;

Swediaur ; Van Mons)

The washed residuum of sulphate of ironsublimed in a retort, constituted the TerraVitrioli dulcis. That of the calcination ofthe natural sulphate of iron, which con-tains zinc and copper, was formerly calledGilla, and was administered as a very mildemetic. It is deservedly no longer used.R. Pure Iron, any quantity.

Dissolve it in

Nitric Acid, a sufficient quantity.

Evaporate the solution to dryness. Cal-cine the residuum, wash it well and dry it.(Fuld.)

R. Iron Filings, any quantity.

Expose them in a crucible to a red heat,till they become converted into a mass of afine red colour. Reduce it to fine powder.(Ant. ; Palat.)

Magisterium Vitriolis Martis. — Magis-tery of the Sulphate of Iron.

R. Sulphate of Iron, any quantity.

Having dissolved it in water, filter thesolution, and precipitate it with that of sub-carbonate of potass. Wash well the preci-pitate, calcine it to redness, and preserve it.(Palat.)

Crocus Martis sulphuratus. — Saffron ofMars by Sulphur.

R - S^mrT'} of each, any quantity.

Calcine the mixture in an earthen pan,stirring it frequently with an iron spatula.Repeat the operation till the metal is con-verted into a red powder : wash and dry it.(Sard.)

Bruns. ; and Wirtem. prescribe fourparts of filings and twelve of sulphur. —