VI. METALS.— Oxides of. 235 



ARSENIC. 



Black ARSEKic, Metallic arsenic, Begulus of arsenic, Arsenic, 

 Arsenicum nigrum, Begulus arsenici. From powdery white arsenic 

 distilled with charcoal dust and some iron or lime to hinder any 

 sulphur from rising. Used to whiten copper; equivalent 4*75. 



Cobalt, Mort a mouches, Fliegen stein. A mixture of black 

 and white arsenic collected in the neck of the distilling vessels in 

 making black arsenic : sold to poison flies. 



NICKEL. 



SriK-s. A metalHc compound that collects at the bottom of 

 the pots in making smalt ; used to make nickel. 



White copper, Pak fong, Tutenague, A compound m^al 

 brought from China ; contains 15 nickel, 28 spelter, and 21 cop- 

 per, malleable. 



METALLIC OXIDES. 



GOLD. 



Purple precipitate, Cassius"* purple, PrcBcipitatum Cossii. 

 Solution of gold in aqua regia, 1 oz., distilled water lib. and a 

 half; mix, and hang in the liquid slips of tin. 



2. Precipitate a dilute solution of gold by a dilute solution of 

 muriate of tin, with a shght excess of acid. Used to communi- 

 cate a purple colour to glass, when melted in an open vessel : in 

 a close vessel the glass receives no colour. 



Crocus of cold, OxzV/c of gold. Crocus soils. Dissolve gold 

 in aqua rc^ia made of common salt, add subcarb. of potash q. s. 

 to ] ' ' the whole. Used in venereal and scrofulous com- 



plaiL- . . > to colour glass purple, but it is difficult to produce 

 by either of these means an equable colour. If heated strongly, 

 it recovers its metallic lustre, and may be used for true gold 

 powder. The gold that remains in the solution being nearly one- 

 half, is separated by adding a solution of green vitriol. 



quicksilver. 



j^THi. . . .... By shaking quicksilver in a lar"-" b'»ftlo, 



or by triturating it with water ; pulverulent, black. 



IIVDnAUGYRI OXYDUM CINEREUM, P. L. Boil caloniL'l />) in 



a gallon of lime-water; wash the grey sediment with water, and 

 dry it. Comp. of ^5 quicks, and 1 oxyg. ; cquiv. 26. 



Protoxide of quicksilver, J'ulris hgdrargyrl cinereus. 

 Quicksilver 3ij, dilute nitric acid 3ij, distilled water 3viij, aqua 



