252 VI. METALS.— Salts. 



and in mines, black, hard enough to cut glass, with an imperfect 

 metallic lustre. Used for making chrome yellow. 



Chrome yellow, Chromate of lead. Prepared from chro- 

 mate of iron, by heating it with nitre or pearl-ash ; washing the 

 mass, and mixing the ley with a solution of lead in nitric acid, or 

 of sugar of lead in water; it should not effervesce with nitric 

 acid ; used as a gold-colour paint. 



METALLIC SALTS. 



GOLD. 



Muriate of gold, Chloride d'^or, Murias auri, Chloruretum 

 auri. Grain gold ^j, nitric acid at 36 deg. Baume ^j, muriatic 

 acid at 22 deg. Baume ^iij ; dissolve with heat until the smell of 

 chlorine gas is perceivable, then set it by to crystallize. Used in 

 venereal complaints, and as a caustic in cancerous affections. 



Solution of muriate of gold, Hydrochlorate d'or en solu- 

 tion. Dissolve the muriate of gold in water. Used to discover 

 oil in distilled waters. 



Soda muriate of gold, Chloruretum auri et sodii, Aurum 

 muriaticum natronatum. Grain gold ^ij make into muriate of 

 gold, dissolve the crystals in water 3X ; add a solution of decre- 

 pitated salt 3ss in water Jvj, evaporate and crystallize. Dose 

 gr. 1-8 to gr. ij rubbed into the gums, in syphilis ; very uncertain 

 in its action ; it has recently been found serviceable in scrofulous 

 affections, either by frictions or internally in the form of pastilles 

 or pills, or mixed up with extracts. 



platinum. 



Soda muriate of platinum, Chloruretum platini et sodii. 

 Dissolve platinum 3J in aqua regia, q. s. and crystallize ; dissolve 

 the crystals in water, and add a solution of decrepitated salt ^ij 

 in water; evaporate and crystallize. In syphilis gr. Ij rubbed 

 into the gums. 



NiTRO-MURiATE OF PLATINUM, HydrocMorate of platinum. 

 Platinum in small granules ^j, add nitric acid ^j, and muriatic 

 acid Siij : when the reaction has ceased, pour off the acid, and 

 pour on fresh ; repeat this until the whole of the platina is dis- 

 solved, which will require about 20oz. of the aqua regia ; evapo- 

 rate and crystallize. 



Solution of nitro-muriate of platinum. Dissolve the 

 crystallized nitro-muriate in water; used to distinguish solutions 

 of potash from soda. 



