90 



CHEMISTRY. 



Elmntt taste is acrid and metallic, aud it it exceedingly caui- 



, ' tic. It is very soluble in water, and speedily d i- 



_^ .JJ" quesces in the air. When heated, it underg.^s the 



watery fusion ; and, if the heat be increased, the acid 



is drive i off, and the black oxide of copper remains 



in a state of purity. It detonates feebly on burning 



coals. It detonate* when mixed with phosphorus 



and struck upon an anvil. When moistened and 



wrapt up in tin-foil, it sets the tin on fire. It is 



composed of 16 acid, 67 oxide, and 17 water. 



Sp. 2. Ilyperoxymitriate of Copper. This salt 

 may be formed by passing a current of oxymuriatic 

 acid through water, containing oxide of copper dif- 

 fused through it. 



Sp. 3. Muriatcd Copper. Of this salt there are 

 two species, the muriate and oxymuriate. 



Sp. i. Sulphate of Copper. This salt has been 

 long known, and in commerce is distinguished by the 

 names of blue vitriol or blue copperas. It crystallizes 

 in oblique parallelepipeds, has a blue colour, a styp- 

 tic metallic taste, and is employed as a caustic. It 

 is soluble in about four parts of cold water. When 

 exposed to the air, it effloresces very slightly. By 

 heat it is decomposed, and black oxide of copper re- 

 mains. It reddens vegetable blue, and is, in fact, a 

 supersulphate. The real sulphate crystallizes in four- 

 sided prisms, terminated by pyramids. This salt is 

 composed of 49.1 acid, and 50.9 oxide. 



Sulphuric acid does not seem capable of combining 

 with protoxide of copper. 



Sp. 5. Sulphite of Copper. When sulphite of so- 

 da and sulphite of copper are mixed, whitish green 

 crystals of sulphite of copper are deposited. They 

 are sparingly soluble in water. 



Sp. 6. Phosphate of Copper. A bluish green pow- 

 der, insoluble in water. 



Sp. 7. Carbonate of Copper. A beautiful apple 

 green powder, insoluble in water. It is often found 

 native, and is distinguished by mineralogists by the 

 name of malachite. 



Sp. 8. Fluale of Copper, This salt crystallizes in 

 cubes of a blue colour. 



Sp. 9. Borate of Copper. A green powder, scarce- 

 ly soluble in water. 



Sp. 10. Acetate of Copper. This salt was known 

 to the ancients. It is sometimes called verdigris ; 

 though that name is more frequently applied to a 

 subacetate of copper. It crystallizes in four sided 

 truncated pyramids. Its colour is a beautiful bluish 

 green. Its taste is metallic and nauseous ; and, 

 like all the salts of copper, it is poisonous. It is 

 sparingly soluble in cold water, but boiling water 

 dissolve:! about one-third of its weight of it. It is 

 soluble also in alcohol. When exposed to the air, it 

 effloresces. When distilled, it yields acetic acid in 

 considerable quantity. It is composed, according to 

 Proust, of 61 acid and water, and 39 oxide of copper. 



Sp. 11. Succitiale of Copper. Small green crys- 

 tals, not yet examined. 



Sp. 12. Benzoate o/ Copjter. Deep green crys- 

 tals, sparingly soluble in water, and insoluble in al- 

 cohol. 



Sp. 13. Oxalate of Copper. A green-coloured 

 .alt, scarcely soluble in water. 



Sp. 1 i. Tartralc of Copper. Bluish green cryj. Elrmf nt 

 tals, sparingly soluble in water. * f 



Sp. 1 .I. ( 'it nil f ,,/ ( ;>,,, ,: Light green crystal "^ 



Sp. 16. Altai: .;. This salt is preci- ' 



pitated in the state of a bluish while powder, when 

 arseniate of potash is poured into sulphate of copper. 

 It is insoluble in water, unless it contains an excess 

 of acid. It has been found native in Cornwall, in 

 crystals, and has been analysed by Chenevix. There 

 are five varieties of it, differing in the proportion of 

 acid and oxide, in the figure of their crystals, and in 

 colour. 



The oxide of copper likewise combines with white 

 oxide of arsenic, and forms a green powder, usually 

 known by the name of Scheele's green. 



GENUS X. Sails of Iron. 



Most of the salts of iron are soluble in water; the Salt 

 solution has a green, or yellowish, or reddish colour, iron, 

 according to the state of oxidizement of the iron. 

 Prussiate of potasli throws down from these solutions 

 a blue powder, or at least it becomes blue when ex- 

 posed to the air. Hydrosulphuret of potash occa- 

 sions a black precipitate. Gallic acid and the infu- 

 sion of nut-galls throws down a black or purple pre- 

 cipitate. 



Sp. 1. Nilrale of Iron. Diluted nitric acid acts 

 with great energy upon iron, a gas being extricated, 

 which is a mixture of nitrous gas and nitrous oxide. 

 There are two varieties of this salt. 



1 Nitrate. This salt may be formed by dissol- 

 ving iron in nitric acid of the specific gravity 1.16. 

 The action is slow, and little gas is extricated. The 

 iron is in the state of black oxide. The solution can- 

 not be heated or concentrated without converting the 

 iron into red oxide. 



2. Oxynitratc. This salt may be formed by con- 

 centrating the preceding. The liquid assumes a red 

 colour, and the red oxide of iron at last precipitates. 

 The salt may be obtained in crystals, by kcepingni- 

 tric acid in contact with black oxide of iron. The 

 oxide gradually dissolves, and four-sided prisms, near- 

 ly colourless, are gradually formed. They deliquesce 

 in the air. 



Sp. 2. Ht/peroxymuriateoflron. This salt may 

 be formed by passing a current of oxymuriatic acid 

 through water, having red oxide of iron mixed with it. 



Sp. 3. Murialed Iron. Of this salt there are two 

 species, the muriate ai.d oxymuriate. 



1 . Muriate. This salt may be formed by dissol- 

 ving iron filings in muriatic acid, without the contact 

 of the external air. The solution is green, and yields 

 green coloured crystals, very soluble in water. The 

 solution absorbs nitrous gas in great abundance. 

 When exposed to the air, it absorbs oxygen, and the 

 salt is converted into oxymuriate. 



2. Oxymuriate. This salt may be formed by ex- 

 posing the preceding to the atmosphere, or by dis- 

 solving red oxide of iron in muriatic acid. The 

 solution has a dark brown colour ; the salt does not 

 crystallize, but when evaporated to dryness, leaves 

 a yellow-coloured mass, which deliquesces, and is so- 

 luble in alcohol. When heated, oxymuriatic acid is 



