264 



Mr Silliman on the 



other shells with reference to this point would have been 

 highly interesting, and had it fallen within the scope of these 

 researches, the subject would have been farther investigated. 

 The per-centage of phosphates and fluorides in the above 

 analyses, after excluding the organic matter, is as follows : — 



It now remains to give the constitution of the precipitat e 

 of fluorides and phosphates. The results annexed are cal- 

 culated for a hundred parts of the precipitate. 



The foregoing results shew, that, contrary to the expecta- 

 tion when the research was commenced, the fluorine is pre- 

 sent in much larger proportion than phosphoric acid. The 



