88 



CHEMISTRY. 



Klrmentt droiulphuret of potash a black precipitate in these 

 ,, ' *olut'"ns. 



_?""!?- S P- ' Kitrate of Sl t -r r . There are two specie* 

 of tni s:.it ; the first, wh' n long known, 



is ai< ozynitrate ; the seconi), recently discovered by 

 Proust, is a nitrate. 



1. Oil/nitrate. Nitric acid dissolves gflver with 

 facility, nitrous gas being emitted. The solution is 

 colourless and transparent ; very heavy and very caus- 

 tic. It tinges the skin of an indelible black, and i 

 often used a* a cautery. When evaporated sufficient- 

 ly, it deposites crystals of oxynitrate of silver. They 

 arc usually in thin plates, transparent, and have an 

 intensely bitter and metallic taste. It does not deli- 

 quesce, but becomes brown in a strong light. When 

 heated, it readily melts, and congeals, when cold, in- 

 to a grey miss, crystallized in needles. In this state 

 it is cast into small cylinders, and used under the 

 name of lunar caustic by surgeons, to open ulcers, 

 and destroy fungous excrescences. It detonates when 

 heated with combustibles, or when struck with phos- 

 phorus upon an anvil, and the silver is reduced. A 

 moderate heat disengages the acid, and reduces the 

 silver to the metallic state. It is composed of about 

 seventy peroxide of silver, and thirty nitric acid. 



2- Nitrate. This salt may be formed by boiling 

 powder of silver in a saturated solution of oxynitrate 

 of silver. A pale yellow coloured liquid is obtain- 

 ed, which contains nitrate in solution. This salt is 

 exceedingly soluble in water> and is not easily cry- 

 stalli/ed. When sufficiently evaporated, it congeals 

 entirely into a solid mass. When exposed to the air, 

 or mixed with nitric acid, it speedily absorbs oxygen, 

 and is converted into oxynitrate. 



Sp. 2. Ili/peroiymuriate of Silver. This salt may 

 be obtained by boiling phosphate of silver in hyper- 

 oxymuriate of alumina. It is soluble in two parts 

 of warm water ; as the solution cools it crystallizes 

 in small rhomboids, opake and dull like- nitrate of 

 lead. It is soluble'in alcohol. When exposed to a 

 moderate heat, oxygen gas is given out and muriate 

 of silver remains. When mixed with sulphur, and 

 struck upon an anvil, it detonates with prodigious 

 violence. 



Sp. 3. Sulphate of Silver. This salt may be form- 

 ed by boiling powder of silver in sulphuric acid. A 

 white mass is obtained, soluble in diluted sulphuric 

 acid, and yielding crystals by evaporation. The 

 crystals are small prisms. They dissolve in about 

 87 parts of water. They dissolve also in nitric acid. 

 They melt when heated, and arc easily decomposed, 

 the silver being reduced. It is composed of about 

 17.4 acid and 82.6 peroxide of silver. 



Sp. 4. Sulphate of Silver. This salt may be ob- 

 tained by mixing sulphate of ammonia and nitrate of 

 silver. It is a white powder, scarcely soluble in wa- 

 ter, and having an acrid metallic taste. In the light 

 it becomes brown. When heated it is decomposed, 

 and the silver reduced. 



Sp. 5. Phosphate of Silver. This is a white pow- 

 der, insoluble in water, but soluble in nitric acid. 



Sp. 6. Carbonate of Silver. This is a white inso- 

 luble powder, which become* black when exposed 

 to the light. 



This it t white powder, 



PlrmrnH 

 of 



This likewise it a white 9 hemi ' try ; 



Sp. 7. Finale of Silver. 

 insoluble in w.itrr. 



Sp. 8. Horate of Silver. 

 insoluble powder. ' 



Sp. 9. Acrlatr of Silver. This salt crystallizes in 

 small prisms, cr-ily soluble in water. When heated 

 it Bwells, and yields a portion of ethereal liquor. The 

 silver is reducr-1. 



Sp. 10. litnzoate of Silver. This salt is soluble 

 in water, and does not deliquesce. 



Sp. 1 1. Succinatf nf Silver. This salt crystallize* 

 11: thin oblong radiated prisms. 



Sp. 12. Oxalntc of Silver. Th'sisa white powder, 

 scarcely soluble in water, insoluble in alcohol, but 

 soluble in nitric acid. 



Sp. 13. Tartrate of Silver. This salt is soluble 

 in water. 



Sp. H. Citrate of Silver. This salt is insoluble 

 in water. It is decomposed by nitric acid. 



Sp. 15. Saccolate of Silver. A white insoluble 

 powder. 



Sp. 16. Malate of Silver. A white powder. 



Sp. 17. Arseniate of Silver. An insoluble brown 

 powder. 



Sp. 18. Chromate of Silver. A beautiful crim- 

 son powder, which becomes purple when exposed to 

 the light. 



Sp. 19. Molybdate of Silver. A white flaky pow- 

 der. 



GENUS IV. Salts of Mercury. 



Mercurial salts when strongly heated are volati- Salts of 

 lized, and traces of mercury may sometimes be ob- 

 served. The prussiates occasion in them a white 

 precipitate ; hydrosulphuret of potash, a black pre- 

 cipitate ; and infusion of nutgalls, an orange yellow 

 precipitate. 



Sp. 1. Nitrate of Mercury. There are two spe- 

 cies of this salt, first correctly distinguished by Berg- 

 man, namely the nitrate and otynitrate. 



1. Nitrate. This salt is obtained by dissolving 

 mercury in diluted nitric acid without the assistance 

 of heat. The solution is colourless, very heavy, and 

 caustic. It tinges the skin indelibly black. It cry- 

 stallizes in transparent octahedrons, having their angle* 

 truncated. Sulphureted hydrogen gas passed through 

 the solution of this salt, reduces the mercery, which 

 separates in combination with sulphur. Muriate of 

 tin throws down the base in the state of running 

 mercury. 



2. Oxynitrate. This salt is formed when nitric 

 acid is made to dissolve mercury with the assistance 

 of heat ; provided an excess of mercury be not pre- 

 sent. By continuing the heat, the solution passes 

 into a yellow coloured crystalline mass. When di- 

 luted with water, a white or yellow powder separate*, 

 which is a suborynilrate of mercury. 



Sp. 2. Hyperoiymiirintt of Mercury. Mr Che- 

 nevix obtained this salt by passing a current of oxy- 

 muriatic acid through water, in which red oxide of 

 mercury was diffused . By evaporating the solution, 

 crystals of oxymuriate and hypcroxymuriate of mer- 

 cury were depotited. The latter were picked out 





