[ * 9 * ] 
I mud here further obferve, that the volcano of 
Poligne did not, perhaps, ceafe to flame on the 
upper part of the mountain, till after the ligneous 
parts of the wood buried in it ceafed to furnifli the 
pabulum neceffary to the fire. 
I fhall be happy, if thefe obfervations merit the ap- 
probation of this illudrious Society, to whom I have 
the honour to dedicate them ; but, however, am de- 
lighted, that they procure mean oceafion of tedifying 
my zeal for this relpedfable and learned body, in 
communicating to it all obfervations, which appear to 
me ufeful. 
However, I do not abfoluteiy pretend, that all 
Tripoli is a wood, wholly or per totiun petrified, and 
afterwards calcined’ by the fubterraneous fire. There 
are Tripolis of many kinds, as well as of feveral de- 
grees of goodnels ; and among thefe there may be 
fuch, as are not otherwife than a real or native foflii, 
deprived by fire of its primitive hardnefs and weight : 
but yet I believe, that the Tripoli, which has its ori- 
gin from a petrified wood, muft be the heft, becaufe 
naturally it ought to be the fined;, fofted, and the 
bed: calcined. 
London, 8th O&ob. 1757-. 
Remarks on Mr. Hubner’j Paper on 'Tripoli ... 
H E is of opinion, that the different drata, marked 
• in his fpecimina N° 1, a, 5, 4, and 5. are all 
the fame, only under different degrees of calcination. 
But N° 2. feems to differ from the red, as it looks 
like mere charcoal, and appears to be very little, if 
at 
