Existence of Phosphate of Magnesia in Bones. 263 

 . In order to procure the magncsian phosphate in an osseous 

 tase, the bones of oxen, after being calcined white and we 1 

 pulverized, must be treated with an equal quantity ot sul- 

 phuric acid ; after being allowed to rest five or six days the 

 mixture is diluted, at first with ten times and aiterwards 

 with five times its weight of water. The liquor i« drained 

 every time ; ammonia in excess is poured into all the liquors 

 Biixed together; and as these liquors, which were formerly 

 supposed to be the phosphoric acid, contam pho^phate ot 

 linieand phosphate of magnesia dissolved in the phosphoric 

 acid, in proportion as the ammonia saturates the acid, a mix- 

 ture of calcareous phosphate and ammoniacal magncsian 

 phosphate is precipitated. This precipitate when washed 

 with a Utrle cold d.siiUed water is trx^tcd with a ley ot pure 

 potash, by boiling them together until no more ammonia 

 is di.eno-a.red. The ammoniacal magncsian phosphate is 

 decompose^d bv this process. The ammonia volatilizes 

 the phosphoric' acid unites itself to the potash, and the salt 

 resulting from it remains in solution ; the free magnesia de- 

 posits itself in powder, and mixes with the phosphate of 

 lime at the bottom of the liquor. The latter is now drawn 

 off clear, theprecip;tat<. is washed, andboili«g distilled vine- 

 car is poured upon it, which dissolves the magnesia without 

 Touchmcr the calcareous phosphate; the magnesian acetate 

 is decomposed bv carbonate of sod:u and we have the car- 

 bonate of magnesia, which is dried, of which the weight is 

 determined, and which is dissolved in the sulphuric acid m 

 order to obtain it in the state of sulphate of magnesia, the 

 form under which it is moi'e generally and more certainly re- 



cognised. . , 



Bv repeating this process a great number of times, in the 

 first' place to ascertain the discovery of the phosphate ot 

 magnesia in the bones of animals, and secondly to appre- 

 ciate the proportion of it, we ascertained that the acetic acid 

 aUvavs dissolves a little lime with the magnesia, and thatthus 

 !ime'could not proceed from any thing else than the decom- 

 position of a small portion of the calcareous phosphate 

 by means of potash : thus, in spite of the laws ot athnit.es 

 hitherto determined, it appeared evident that potash sepa- 

 H 1 rales 



