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It has been believed that zeolites apper- 

 tain exclurively to volcanized countries, 13 nee 

 thej are mod frequently found there ; and 

 my obfervations may appear to confirm this 

 opinion. It however admits of no doubt 

 that they are likewife often found in coun- 

 tries that exhibit no figns of volcanization ; 

 this having been inconteftably proved by 

 Cronftedt, Linnaeus, Bergmann and others. 



It appears equally certain that the zeolites 

 of volcanos do not derive their origin from 

 fire, but are adventitious to thofe places; 

 DOt that they were pre-exiftent to the vol- 

 canic eruptions, and taken up by, and in- 

 corporated with, the currents of lava, as a 

 £elebrated volcanift has fuppofed. They 

 were, no doubt, generated after the extinc- 

 tion of the conflagrations ; when their con - 

 fliituent parts being depofited by water in 

 the cavities of the lava, and there combin- 

 ing by affinity, formed thefe flony fub- 

 llances, according to circumftances, fome- 

 times amorphous, and fometimes cryftal- 

 lized ; in the fame manner that we have 



fuppofed. 



