{ 74 ) 



I was, however, able to afcertain that the 

 fecond and fixth fpecies contained filex in 

 a greater proportion than it was found in 

 the zeolite analyfed by Pelletier ; which 

 perhaps was the caufe that thefe two fpecies 

 do not form a gelatinous fediment ; the fu- 

 perabundance of quartzofe earth not per- 

 mitting the acids to extract the lime and 

 alumine, and thus diflbive the union of the 

 conftituent principles of the zeolite. 



The gelatinous diflblution of the zeolite 

 is neither a quality found in every fpecies, 

 nor is it peculiar to it, fmce experience has 

 fliewn that it is common to other ftones, the 

 conftituent principles of which are the fame 

 with thofe of the zeolite, and combined in 

 a certain proportion. This identity of prin- 

 ciples, which, in fome fpecies of ftones, af- 

 fords, by means of the adion of acids, the 

 fame gelatinous produd:, induced me to 

 make an experiment, of which I fhali here 

 give the refult. 



The colourlefs garnets of Vefi^vius con- 

 tain, 



