O F F O S S I L S. 



5 cxxn. Double imperfctt earthy Salts. 



OF all the double imperfect earthy falts, with 

 an cxcefs of acid, the fait of alum is the moft 

 ") confpicuous. 



5 cxxiu. Triple earthy Salts, 



THE principle triple compounds, arc the vo- 

 latile alkali, either vitriolated or muriarcd, and 

 magnclia, with which even nitrated lime readi- 

 ly unites. Vitriolatcd magnelia combines with 

 clay ; and both the vegetable and mineral alka- 

 li faturatcd with the acid of fluor, admit an uni- 

 on with iiliceous earth* 





cxxiv. Earthy alkaline Salts. 



FIXED cauflic alkalis, 1 know for certain af- 

 fed no other earths than the argillaceous and 

 filiccous. No triple alkaline falts have as yet 

 been difcovercd. 



j cxxv. Speciei qf metallic fahs. 



ANALOGICAL metallic falts arc by far the 

 moft numerous. From a combination of the 

 fixteen metals with the twenty acids, we ob- 

 tain. three hundred and twenty double falts; 



but 



