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though they reduce the fifth to gelatinous 

 flakes or tufts. The fire of the furnace, in 

 half an hour, converts the cryftals of the 

 fixth fpecies into globules of extremely 

 tranfparent glafs ; whereas it only foftens, 

 in that time, the minute fpheres of th^ fifth, 

 which require a fire of much longer con- 

 tinuance for their complete liquefa<flion ; 

 and the globule, which then refults, is an 

 opake glafs, of the colour of milk. Both, 

 however, have the property which is ufu- 

 ally common to zeolites ; I mean that of 

 phofphorefcence at the moment of fufion ; 

 as may be feen by employing oxygenous 

 gas. 



After having made thefe experiments on 

 the .zeolites of Lipari, I was induced to 

 examine one of thofe of Iceland, which 

 have the character of being the mofl ex- 

 cellent for forming a gelatinous body. I 

 certainly obtained from it, very readily, an 

 extremely beautiful jelly ; but not in the 

 Jeaft fuperior to that produced by the third 

 F 3 and 



