238 VI. METALS.— Oxides of. 



Crocus martis, Peroxide of iron^ Potee d'acier, C. martis 

 astringens^ Oxidum fei^i ruhrum. Calcine iron or steel filings till 

 they become of red colour. Composed of 35 iron and 1'5 ox. ; 

 equiv. 5. 



Crocus martis aperitivus, P. L. IT^O, C. M. sidphiwatics. 

 Melt together equal parts of iron filings and sulphur, and calcine 

 the mass till all the sulphur is driven off. 



Rough colcothar, Brown red, Common Indian red. Rouge 

 d^ Angleterre. By recalcining green vitriol (previously calcined to 

 whiteness, or distilled for its oil,) until it becomes very red. 



Washed colcothar, Indian red. Trip, Terra dulcis vitrioli. 

 Wash rough colcothar, or the residuum left in the distillation of 

 aquafortis, till all the saline matter is abstracted ; scarlet. 



Crocus. Calcine washed colcothar in a violent heat, until it 

 becomes purplish or bluish ; very hard ; used for polishing. 



Fine crocus. Green vitriol and salt, of each' lib., grind toge- 

 ther, heat to a cherry red for some hours, and wash ; violet 

 brown, soft to the touch ; spread with soap upon razor-strops. 



Jewellers'* rouge. Precipitate a solution of green vitriol in 

 water, by a solution of pearl ash, and calcine till of a scarlet 

 colour. 



All these are tonic, stimulant, gr. v. to x. Used in the com- 

 position of astringent drying and strengthening plaisters and 

 ointments ; employed also for polishing metals, and as pigments. 



TIN. 



Stannum pulveratum, p. L. 1788. Tin 61b., melt, and 

 stir till it becomes covered with a powder, which take off, and 

 when cold sift. 



Potee d'etain, Polisher's putty ^ Calcine^ Cineres stanni. Melt 

 tin, rake off the dross as it is formed, and calcine this dross till it 

 becomes whitish. 



2. Melt tin with an equal weight, or one ounce and a half of 

 lead, and then raise the heat so as to render the mixed metal red 

 hot, when the tin is immediately flung out in the state of putty. 

 Both are very hard, used for polishing glass and japan work, and 

 to colour opaque white enamel. 



Bezoardicum Joviale, Peroxide of tin. Tin 1 oz., nitre 

 3 oz., flung into a red hot crucible, and the calx well washed; 

 composed of 7*25 tin with 2 oxyg., equiv. 9*25. 



Antichecticum Poterii. Tin, regulus of antimony, ana p. 

 aeq. melted together, then deflagrated with three times as much 

 nitre, and well washed ; are astringent, 3j to ij ; used in phthisis. 



