Salts. 177 



The Phofphoric has as yet been difcovered 

 only in foffile bones, and in one fpecies of 

 lead ore. It probably owes its origin to the 

 decornpofition of bones. 



The Molybdenous acid being very lately 

 known, has been found only in molybdena. 



The Arfenical acid has been traced in the 

 ores of other metallic fubftances, particularly 

 of cobalt. 



The Tung ft en acid has hitherto been found 

 only in the calcareous ftone, called Tungften. 



CHAP. II. 



Of Alkalis. 



Thefe are of two forts, fixed and volatile; the 

 fixed are either of vegetable or mineral origin, 

 which differ in a few properties, but it is to 

 be obferved, that forae vegetables afford alfo 

 an alkali intirely fimilar to that of mineral 

 origin, particularly marine plants, or thofe 

 that grow near the fea ; neither of them is 

 ever found in a cauftic ftate, but all are com- 

 bined at leaft with the aerial acid. They 

 then effervefce with moft other acids, turn 

 infufions of blue flowers of certain vegetables 



N green, 



