CHEMISTRY. 



91 



Elementt given out, and black oxide of iron remains still com- 

 bined with muriatic acid. 



[[ Sp. 4. Sulp/iated Iron. Of this salt, likewise, there 

 ' are two species, the sulphate and oxysulphate. 



1. Sulphate. This salt was known to the ancients, 

 and is used in considerable quantity in dyeing, and 

 in the manufacture of ink. It is easily obtained by 

 dissolving iron in diluted sulphuric acid, and evapo- 

 rating the solution. It has a green colour, sometimes 

 very light, sometimes very dark. In this last state 

 it is preferred by artists. Upon what the difference 

 depends is not accurately known. It crystallizes in 

 rhomboidal prisms. It has a very styptic taste, and 

 always reddens vegetable blues. It is soluble in two 

 parts of cold, and in less than its weight of boiling 

 water. It is insoluble in alcohol. When alkali is 

 poured into a solution of this salt, a white powder 

 precipitates, which is a subsulphate of iron. When 

 heated, it melts, and loses its water of crystallization. 

 In a red heat, it loses most of its acid, and is con- 

 verted into a red powder, known by the name of col- 

 cothar of vitriol, and used in polishing glass and me- 

 tallic bodies. This salt is composed of 26.7 acid, 

 28.3 base, and 45 water. 



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

 posing the solution of the preceding to the open air. 

 It has a yellowish-red colour, does not crystallize, 

 and when evaporated to dryness, soon attracts mois- 

 ture, and becomes again liquid. 



Sp. 5. Sulphite of Iron. Iron dissolves in sul- 

 phurous acid, without the emission of much gas. 

 The solution yields crystals of sulphite, which are 

 soon changed into sulphate by exposure to the air. 



Sp. 6. Photphated Iron. Of this salt there are 

 two species, the phosphate and oiyphosphate. 



1. Phosphate. This salt may be obtained by mixing 

 solutions of phosphate of soda and sulphate of iron. 

 It precipitates in the state of a blue powder. It is 

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

 It is found native, crystallized in blue -coloured prisms. 



2. Oxyphotphate. This is a white powder, inso- 

 luble in water, but soluble in acids, and precipitated 

 by ammonia. When violently heated, it melts into 

 an ash-coloured globule. When treated with a fixed 

 alkali, it loses a portion of its acid, and is converted 

 into a brown-coloured powder. In this state it is a 

 sitbo.ii/phosphate of iron. It is insoluble in water, 

 and nearly so in acids. But it dissolves in the serum 

 of blood, and is supposed by some to give the red 

 colour to blood. 



Sp. 7. Carbonate of Iron. This salt may be ob- 

 tained by precipitating sulphate of iron by an alka- 

 line carbonate. It has been found native, crystallized 

 in rhombs, somewhat transparent, of a greenish-yel- 

 low colour, and brittle. It is composed of 36 acid, 

 59.5 protoxide, and two water. Rust is frequently 

 a carbonate of iron. Hence it effervesces when dis- 

 olved in acids. 



Sp. 8. Fluate of Iron. Fluoric acid dissolves iron 

 readily. The solution does not crystallize, but as- 

 sumes the form of a jelly. 



Sp. 9. Borate of Iron. A yellow powder, inso- 

 luble in water. 



Sp. 10. Acttated Iron. Of this salt there are two 

 specks, the acetate and oxacetate. 



A deep blue or black 

 The prussiatc is a white 



1. Acetate. It may be obtained by dissolving sul- Element! 

 phuret of iron in acetic acid. It forms green-colour- 

 ed prismatic crystals, sufficiently soluble in water. V_ 



2. Oxacetate. A reddish-brown liquid, which does 

 not crystallize, but is easily converted into a jelly, 

 which deliquesces. This liquid is much used by ca- 

 lico-printers. 



Sp. 11. Succinate of Iron. A brownish red pow- 

 der, insoluble in water, unless there be an excess of 

 acid present. 



Sp. 12. Benzoate of Iron. Yellow crystals, with 

 a sweet taste, soluble in water and in alcohol. . 



Sp. 13. Oxalated Iron. Oxalic acid attacks iron 

 rapidly, and combines with both its oxides. 



1. Oxalale. Prismatic crystals of a green colour, 

 very soluble in water, with an excess of acid. 



2. Oxygenized Oxalote. A yellow powder, scarce- 

 ly soluble in water, and incapable of crystallizing. 



Sp. 14. Tartrated Iron. The tartrate crystalli- 

 zes, and is sparingly soluble in water ; the oxylartrale 

 is red, does not crystallize, but runs into a jelly. 



Sp. 15. Citrate of Iron. A brown coloured so- 

 lution, which deposites small crystals, very soluble in 

 water. 



Sp. 16. Malate of Iron, A brown solution which 

 does not crystallize. 



Sp. 17. Collate of Iron. 

 powder, insoluble in water. 



Sp. 18. Prussiated Iron. 



powder, the oxyprussiate a deep blue powder ; both 

 insoluble in water. 



Sp. 19. Arseniated Iron. The arseniale is a green- 

 coloured salt, insoluble in water, found native, cry- 

 stallizes in cubes. The oxarseniate is a brownish-red 

 powder, likewise insoluble in water. 



Sp. 20. Tungstate of Iron. An insoluble powder 

 of a grey colour. 



Sp. 21. Moiybdate of Iron. AD insoluble brown 

 powder. 



Sp. 22. Columbate of Iron. An insoluble mineral 

 of a dark brownish-grey colour, and a lamellated 

 structure. 



GENUS XI. Salts of Tin. 



Most of these salts are soluble in water, and the Salts of 

 solution is colourless, or has a brownish colour, ac- tin. 

 cording to circumstances. The prussiates, when 

 dropt into these solutions, occasion a white precipi- 

 tate; hydrosulphuret of potash occasions a brownish 

 black, or a golden yellow precipitate ; corrosive sub- 

 limate occasions a black or a white precipitate ; in- 

 fusion of nut-galls occasions no precipitate in these 

 solutions. 



Sp. 1. Nitrated Tin. Nitric acid acts with great 

 violence on tin, and speedily converts it into an oxide. 

 When the acid is much diluted, it forms a yellow co- 

 loured solution, containing deutoxide of tin. But 

 when the solution is left to itself, or when it is con- 

 centrated by evaporation, the oxide of tin is precipi- 

 tated. When the acid is strong, it speedily converts 

 the metal into peroxide without dissolving any of it. 

 During the action ammonia is formed, and remains 

 in combination with the acid. 



Sp. 2. Muriated Tin. Muriatic acid dissolves 



