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Giol'fofet ptead example; as not one of my predecessors, 

 who have written upon this topic, has (so far as I cau'!^ 

 find) examined botli volcanic countries, and our basaltic 

 one. ' y'j-iit- • . 



I ha^^ latso amthority for saying, that an examination 

 of existing volcanos is not very instructive. Mr. Kirwan 

 ■tells W3, Collini, twice ascended Vesuvius, and witnessed 

 its eruptions; but complains, he got no knowledge by it. 

 Mr. Ferber's testimony is exactly similar. And, indeed, it 

 is plain y that, in. an- eruption, the lighter materials first 

 projected upwards; then, falling down, and accumulating 

 upon the weightier, that had flowed in lava, must make 

 it very difficult to trace arrangement: and this is the 

 fenarest guide, in all questions relative to cosmogony. 



Mr. Strange's observations on this topic are amusing: he 

 ^ets Out the secret, without knowing it, or availing him- 

 self of it- He says, " The phaenomena of I'ecent volcanos 

 " are very little calculated to give us instruction. A few 

 " days tour in Auvergne, Velay, or the Venetian State, 

 " are worth a seven years apprenticeship at the foot of 

 ■" Vesuvius or iEtna." 



Mr. Strange was not aware, that Auvergne, Velay, and 

 the parts of the Venetian state he alludes to, were ori- 

 ginally basaltic countries, in which, afterwards, volcanos 

 erupted. Here he found a rich variety of materials: for, 

 besides the common volcanic substances, he found all the 

 varieties of basalt, with the matters that usually accom- 

 pany them, ochres, zeolites, chalcedonies, and calcareous spar; 



while 



