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Though it was not known till the pre- 

 fent time that Lipari afforded volcanic chry- 

 folites, they had been before found in other 

 volcanized countries, as in Vivarais and Ve- 

 lay, by M, Faujas, and on Mount Etna by 

 M. Dolomieu. But on comparing their chry- 

 folites with mine, I find certain differences 

 and refeaiblances, which it will be proper to 

 enumerate. 



The chryfolitcs obferved and defcribed 

 by M. Faujas, when examined with the 

 lens, are found to be compofed of an aggre- 

 gate of arenaceous grains, more or lefs fine, 

 and more or lefs adherent ; fcabrous, irre- 

 gular, and fometimes forming crufts and 

 fmail fandy fcales ; but, for the mod part, 

 having the appearance of angular fragments 

 united by infertion into each other. 



The chyfolites of Lipari have nothing of 

 this nature in their ftrudure. I broke fe- 

 veral of them, and examined their frag- 

 ments with the microfcope -, but they never 

 appeared to me granular, but always fmooth 



D 3 and 



