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tain, according to Bergmann, ^^ parts of 

 filex, 39 of alumine, and 6 of lime. As, 

 therefore, I had colled:ed a confiderable 

 quantity of thefe at Vefuvius ; I determined 

 to make experiments on them with acids, 

 in the fame manner I had done on the zeo- 

 lites. But in the three firft varieties which I 

 pofTefs, though I had firft reduced them to 

 powder, no gelatinous fubftance was pro- 

 duced. With the fourth I fucceeded ; though 

 I did not make the experiment on the fame 

 garnets, for the attempt would have been in 

 vain, but on others, of the fame fpecies, 

 which I have not mentioned, and which 

 had been greatly foftened by the fulphureous 

 acids, though they retained their four-and- 

 twenty facets. Thefe the nitric acid, after 

 thirteen hours, reduced to a jelly, though 

 not one fo beautiful as that obtained from 

 the zeolites. We may therefore conclude, 

 that this aptitude to diffolution was produ- 

 ced in the garnets by the alterations they 

 had fuffered ; in confequence of which the 

 nitric acid, penetrating their internal parts, 

 had aded on them as it adls in many zeolites. 



It 



