236 VI. METALS.— Oxides of. 



sLibcarbonatis ammonias q. s. (about ojss), to precipitate the 

 oxide : wash and dry. 



OXIDUM HYDRARGYIU CTNEKEUM, P. E. Quicksilver jiv, 



dilute nitric acid 5v, distilled water 3xv, aqua subcarbonatis am- 

 monia; q. s. Dissolve the metal in the acid, dilute the solution 

 with the water, precipitate with the alkali : wash and dry the 

 precipitate. Totally different from the London oxide of the same 

 name : all these are used in syphilis, and are not apt to disorder 

 the stomach and bowels. Dose gr. j — iij, bis in die. 



Calcined mercury, Precipitate j^er se^ Peroxide of quicksilver^ 

 Mercurius prcEcipitatus per se, Mercurius calcinatits, Hydrargijrus 

 calcinatus, Hydrargyri oxidiim ruhrum^ Oxidum hydrarrjyri. By 

 exposing a thin stratum of quicksilver to the action of heat suffi- 

 cient to keep it boiling, in a flat-bottomed matrass, called Boyle\s 

 hell, contrived to admit air without letting the vapour of the 

 quicksilver escape. In red scales, darker than red precipitate ; 

 may be used for the same purposes. Comp. of ^25 quicks., 

 2 oxyg. ; equiv. 21, 



Red precipitate, Mercurius corrosivus ruber. Quik, aq. 

 fortis composita, ana Ib.j ; dissolve, decant, and evaporate on a 

 sand heat, until it becomes red. 



Hydrargyrus nitratus ruber. Quik, nitric acid, ana 

 ^xij, acid muriat. 3] ; dissolve and evaporate to dryness. 



Mercurius pr/ECIPITatus corrosivus, Hydrargyri nitrico- 

 oxidum, Oxidum hydrargyri iiitricum^ Oxidum hydrargyri ruhruiii 

 per acidum nitricum. By dissolving quicksilver in nitric acid, 

 with heat, and evaporating till a dry mass is left, which is then 

 calcined in a broad, shallow vessel, until it no longer emits red 

 vapours. 



2. Quik 36 oz., dissolve in aquafortis 60 oz., digest two days 

 to clear it, distil to dryness in a gallon retort, pour on a similar 

 solution, and distil again to dryness: for this, six retorts are 

 required, set in a sand heat : calcine the mass in three retorts, 

 with receivers, set in separate furnaces. In the first three hours, 

 flowers should settle in the arch of the retorts ; in the next three, 

 they should be driven into the neck ; in the last three, the matter 

 in the retorts should become first yellow, then orange, lastly ver- 

 milion red; the fire being then stopped, the residuum will be a 

 shining red scaly mass, of a proper marketable quality. The 

 aquafortis that comes over may be used over again, adding a 

 quarter of fresh acid. Anti-syphihtic, gr. ss— ij nocte maneque, 

 but principally used externally, as an escharotic and stimulant to 

 foul ulcers, for which purpose it must be very finely pulverized. 



Green precipitate, Mercurius prcecipitatus viridis, Lacerta 

 mridis. Dissolve quicksilver 5j in nitric acid q. s. ; at the same 



