Elements of Mineralogy. 

 from bones, horns, claws, teeth, &c. was 

 found by Mr. Gabn, to be a calcareous Earth 

 united to the phofphoric acid ; hence the 

 folution of bones in the mineral acids can 

 never be neutralized, a circumftance which 

 puzzled all preceeding chymifts, but which 

 is now perfectly underftood, as fuch folution 

 is in facl: only the folution of a neutral fait 

 if the bones be diflblved in the nitrous or 

 marine acids, or a decompofition of a neu- 

 tral fait, if the vitriolic acid be ufed as a 

 folvent ; in either cafe a free unfaturated acid 

 muft be found. However fome bones con- 

 tain an excefs of phofphoric acid, and fome 

 an excefs of Earth, as ivory, whence fome 

 have imagined this latter to contain a pecu- 

 liar Earth. Some late and accurate experi- 

 ments relating to the proportion of phofpho- 

 ric acid in bones by Mr. Berniard, may be 

 feen in Rozier*s journal, for 1781, p. 280, 

 1782, p. 43. 



The phofphoric acid is feparated from this 

 Earth by calcining the bones to whitenefs 

 then diffolving them in nitrous acid, and 

 precipitating the calcareous Earth by the 

 concentrated acid of vitriol. A felenite is 

 thus obtained (decompofable either by calci- 

 nation with charcoal, or by boiling in a 

 folution of mild fixed alkali,) and the phof- 

 phoric acid remains in the liquor. 



APPENDIX 



