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2(PO,; 3 Ca O) +5 SO,5 HO = PO,3 HO + PO,Ca O 2 HO 
+5 (SO, CaO), 
and the results would be free phosphoric acid, mono-phosphate 
of lime, and sulphate of lime; but the latter is insoluble, or 
nearly so, and the filtered liquid would therefore only contain 
phosphoric acid and mono-phosphate of lime. If to this solu- 
tion, ammonia or any other alkali were added, the most proba- 
ble reaction might be thus represented : 
PO, 3HO+ PO, CaO 2HO+4NH;=PO,+2NH,O 
+HO+ PO, CaO 2 NH, O. 
The free phosphoric acid would form the ordinary phosphate 
of ammonia, and the mono-phosphate would, by appropriating 
two equivalents of ammonia, become an ammonio-phosphate 
of lime. I say this would be the most likely decomposition, 
because, in the absence of the two equivalents of lime requisite 
to make bone earth, the mono-phosphate might be supposed 
to prefer oxide of ammonium to water, the only other ayail- 
able basic element. 
** By digesting dilute phosphoric acid upon bone ashes, and 
filtering, I obtained a solution of mono-phosphate of lime with 
free phosphoric acid. This solution precipitated upon the ad- 
dition of an alkali; but the precipitate differed from bone 
earth by being easily fusible before the blow-pipe flame. 
‘¢ Saussure says, that bone earth fuses at 370° Wedgwood, 
but I never could produce the slightest cohesive effect on it 
by subjecting it to a gas jet urged by the blow-pipe. The 
fusible precipitate thrown down by an alkali from an acid so- 
lution of the mono-phosphate differs in properties according 
to the alkali employed. 
** When precipitated by ammonia it fuses into a transpa- 
rent glass bead in the outer flame, and bubbles violently ; it 
becomes white and opaque when kept long in the inner flame ; 
in fact, it acts exactly similar to metaphosphate of lime, which 
no doubt it is, the ammonia being driven off by the heat. The 
