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II. ExtraB of another Letter^ from Mr» 
Hamilton, to Dr. Maty, on the famt 
SubjeB. 
Naples, March 5, 1771. 
Read May 30, I had the pleafure of fending 
you my letter, in which the nature of 
the foil of more than twenty miles round this capital 
is deferibed ; examining a deep hollow way cut by 
the rain waters into the outlide cone of the Solfaterra, 
I difeovered, that a great part of the cone of that 
ancient volcano has been calcined by the hot vapours 
above deferibed. Pumice calcined feems to be the 
chief ingredient, of which feveral fpecimens of (as I 
fuppofe) variegated uniform marble are compofed, and 
the beautiful variegations in them may have probably 
been occalioned by the mineral vapours. As thefe 
fpecimens are now fent to the Royal Society, you will 
fee that thefe variegations are exadtly of the fame 
pattern and colours as are met in many marbles and 
flowered alabaftersj and I cannot help thinking that 
they are marble or alabafter in its infant ftate. 
What a proof we have here of the great changes the 
earth we inhabit is fubjedl to ! What is now the 
Solfaterra, we have every reafon to fuppofe, to have 
been originally thrown up by a fubterraneous explo- 
fion from the bottom of the fea. That it was long 
i an 
