CHEMISTRY. 



77 



Elements 



of 

 Chemistry, 



Sp. I. Borate of Ammonia. This salt forms per- 

 manent crystals, which resemble those of borax. 

 Heat decomposes it. 



Sp. 5. Borale of Strontian. This salt is a white 

 powder, and contains ar. excess of base. 



The remaining borates are insoluble in water. 



Sp. 6. Borate of Magnesia. This salt may be 

 obtained in small irregular crystals. It is soluble in 

 acetic acid. Alcohol is said to decompose it. When 

 heated, it melts, and is not decomposed. 



Sp. 7. Borate of Lime. This is a white powder, 

 hardly soluble in water, and tasteless. 



Sp. 8. Borate of Barytes. An insoluble white 

 powder, hardly examined. 



Sp. 9. Berate of Alumina. Scarcely soluble, aad 

 not crystalli/able. 



GENUS IV. Phosphates. 



The salts belonging to this genus, when heated 

 before the blowpipe, melts into a globule of glass. 

 They dissolve in nitric acid, without effervescence, 

 and are precipitated from that solutiou by lime-water 

 or ammonia. They amount to twelve. 



Sp. 1. Phosphate of Potash. Of this salt there 

 are two varieties, the superphosphate, long known, 

 and the phosphate, not accurately discriminated till 

 lately. 



Variety 1. Superphosphate. This salt is formed 

 by dissolving carbonate of potash in phosphoric acid 

 till all effervescence cease, and then evaporating the 

 solution. It crystallizes with difficulty in striated 

 prisms. It is very soluble in water, and deliquesces 

 when exposed to the air. When heated, it undergoes 

 the watery fusion, loses its water of crystallization, 

 and is reduced to dryness. I:i a high temperature it 

 melts into a transparent glasn. 



Variety 2. Phosphate. This ealt may be formed 

 by saturating the superphosphate with potash, and 

 exposing the mixture to heat in a platinum crucible. 

 It is usually in the state of a white powder, Usteles , 

 and insoluble in cold water though it dissolves in hot 

 water. It melts easily into a transparent bead, wi.ich 

 becomes opake on cooling. It dissolves in the nitric, 

 muriatic, and phosphoric acids, and is not precipi- 

 tated by alkalies ; but when the solutions are con- 

 centrated, a precipitate falls. 



Sp. 2. Pho'phate of Soda. This salt is usually 

 prepared by decomposing the superphosphate of lime 

 from burnt bones with carbonate of soda. As sold 

 by apothecaries, it is much contaminated by sulphate 

 of soda. It crystallizes in rhomboids! pri ms. Itt 

 taste is similar to that of common salt. It dissolves 

 in four times its weight of cold water. In the air it 

 effloresces. When heated, it undergoes the watery 

 fusion ; and, at a red heat, melts into a white enamel. 



Sp. 3. Phosphate of Ammonia. This salt exists 

 in urine. It is also prepared artificially in the same 

 way as the last species. It crystallizes in four-sided 

 prisms. Iti taste is cooling, salt, and ammoniacal. 

 It is .oluble in four parts of cold water. When heat- 

 ed, it undergoes the watery fu>ion. In a strong heat 

 the ammonia is disengaged, and the phosphoric acid 

 mehs into a glass. 



Sp. *. Phoiphate of Magnetia. This salt may be 



obtained by mixing together concentrated solutions Element 



of phosphate of soda and sulphate of magnesia ; in 



r i * i r i i r i Chemistry. 



a few hours crystals of phosphate of magnesia are de- _ _> 



posited. It crystallizes in six-sided prisms with un- 

 equal sides. It has little taste, dissolves in 15 parts 

 of cold water, and falls to powder when exposed to 

 the air. When heated strongly, it melts into a trans- 

 parent glass. 



Sp. 5. Phosphate of Soda-and- Ammonia. This 

 salt, known by the name of microcosmic salt, may be 

 obtained from urine. It possesses nearly the proper- 

 ties of a mixture of the two preceding species. 



Sp. 6. Phosphate ofAmmonia-aiid-Magnesia. This 

 triple salt exists also in urine. Its crystals are four- 

 sided transparent prisms, terminated by four- sided 

 pyramids. It is tasteless ; scarce soluble in water ; 

 and not liable to be altered by exposure to the air. 

 In a strong heat, it loses its ammonia, and melts into 

 3 transparent glass. 



The remaining phosphates are insoluble in water. 



Sp. 7. Phosphate of Lime. This salt constitutes 

 the basis of bones. It may be obtained by calcining 

 bones, dissolving them in muriatic acid, and precipitat- 

 ing by ammonia. It is then in the state of a white, 

 powder ; but it is found native, crystallized in six- 

 Elded prisms, and is distinguished among mineralo- 

 gists by the name of apatite. It has no taste, is in- 

 soluble in water, and not altered by exposure to the 

 air. A red heat does not alter it ; but in a very vio- 

 lent temperature, it is converted into a kind of ena- 

 mel. It dissolves in the strong acids without effer- 

 vescence, and may be again precipitated by ammonia. 

 The strong mineral acids decompose it partially, 

 and convert it into superphosphate of lime, which is 

 an acid liquid, which crystallizes in thin brilliant 

 plates. 



Sp. 8. Phosphate of Barytes. This is a white 

 tasteless powder, which, in a violent temperature, 

 melts into a grey enamel. 



Sp. 9. Phosphate of Strontian. This is a white 

 powder, insoluble in water, but soluble in phospho- 

 ric acid. Before the blowpipe, it fuses into a white 

 enamel. 



Sp. 10. Photphate of Alumina. A white powder, 

 but tasteless and insoluble in water. 



Sp. 11. Phosphate of Yltria. A gelatinous mass, 

 insoluble in water. 



Sp. 12. Phosphate of Glucina. A white tasteless 

 insoluble powder. 



The following Table exhibits the constituents of 

 the phosphates, according to the experiments of 

 Richter. 



