PHOSPHATES. 435 



(/*.) Partially decomposed by acids, especially the stronger, and 

 even by the vegetable acids. 



4. COMPOSITION. One equivalent of acid, 28, and one of lime, 28. 

 BI-PHOSPHATE OF LIME is easily formed by dissolving phosphate 



of lime in as much phosphoric acid as the salt contains, and it is always 

 formed, (or at least a phosphate with excess of acid,) in the decom- 

 position of bone ashes, as will appear more particularly farther on. 

 The bi-phosphate is very soluble in water and does not crystallize.* 

 It melts before the blowpipe into a transparent globule ; it is insoluble, 

 and doubtless, by the heat, loses the excess of acid. 



Remark. For a notice of Mr. Dalton's views respecting the bi- 

 tri- quadri- octo- and dodeca-phosphate of lime, containing, as is sup- 

 posed, 2, 3, 4, 8 and 12 equivalents of acid, reference may be had 

 to Henry's Chemistry, 10th ed. Vol. I, p. 591. 



5. MINERAL AND ANIMAL PHOSPHATE. 



Found as a mineral in many countries ; in Estremadura, in Spain, 

 forms extensive rocky strata ; it is there used in building. Most of 

 the natural phosphates are highly phosphorescent by heat ; animal 

 phosphates are not. Occurs crystallized in Saxony, Bohemia, Eng- 

 land, United States, &c. in six sided prisms and tables ; it is called 

 apatite and asparagus stone. 



It exists in most animal fluids; in human urine, in the form of 

 bi-phosphate, and is precipitated by lime water and the alkalies ; in 

 milk and blood ; it is found in the muscles and in jelly ; in preter- 

 natural ossifications, and in most of the calculi, whether in the kid- 

 neys or the bladder. It exudes through the skin, and is found in 

 the solid excrements of animals whose urine does not contain it. It 

 is found also in the ashes of both vegetable and animal substances. 



6. PROCESS FOR PHOSPHORUS. f 



(a.) Burn bones in a furnace, or even in a common fire; the oils, 

 gelatine, &ic. will be consumed and the osseous part will be easily 

 pulverized. In an earthen pan or dish, place bone ashes 2 parts, 

 water 20 and sulphuric acid 1 ;J digest them upon embers or by a 

 sand heat, and stir thoroughly, with a glass rod during ten or twelve 

 hours ; throw the mass upon a coarse linen filter, stretched over a 

 frame with tenter hooks; wash the insoluble residuum with boiling 

 water till it comes orT tasteless ; the fluid will be turbid ; let it 

 settle, and then draw it off clear ; evaporate in a clean copper or tin 

 vessel to dryness ; or, it will answer if still moist. 



* Fourcroy says it can be made to crystallize in brilliant micaceous scales. 



t For a series of years, I was in the habit of manufacturing all the phosphorus 

 required in the experiments of the laboratory, and nearly every part of the annexed 

 statement I have repeatedly verified by my own experience. 



t There will be a considerable effervescence owing to carbonate of lime, and as 

 is said, carbonate of soda. 



