( 2l8 ) 



this appearance — Strata of globes neai^ 

 Teolo abounding in particles of pitch -Jl one 

 •"—Feins ofpitch-fonc lavas atBajainonteand 

 Sieva — Groups of pumices enclofed in one 

 of thefe veins — Comparifon^ in the dry 

 ivay^ cf the non-volcanic pitch -f ones ivith 

 the volcanic — Proof by the humid ivar, 

 that both are of the fame kind — EJfential 

 differences bet-ween the pitch fone lavas and 

 the volcatiic gl^ffcs — Volcanic produBions 

 cf Schivanoja^ Monte Merlo^ Mafcabo^ 

 ^remonte and Pendfe^ ivhich have been 

 ftyled volcanic glafs by a living writer y 

 but ivhich in reality can only be called 

 pitch-f one lavas ^ and but one of them ^ at the 

 utuiof^ a vitreous lava — Mi/lake of this 

 author in having taken for volcanic glafs 

 fame pieces cf glafs from the furnaces of 

 Murano^ near Venice^ vohich he cafually 

 found in ihof mountains — Remarks on 

 this accident^ ifjhich fjould teach us to be 

 cautious in forming a judgment ivhether a 

 mountain be volcanic or tiot^ from finding 

 a detached piece of glafs ^ or other produc- 

 tion of the fire J fince it may be uncertain 



whether 



