132 On the geological Theory supported by Mr. Smithson, 
Now, since the author says in favour of his igneous systems 
that no crystal such as quartz has ever been seen inclosing dr ops 
of water, which ought to be the ease in that system ; the con- 
trary being the fact, is a peremptory proof against it. 
I now come to the inferences which the author derives from 
the phenomena of volcanoes, making however this previous re= 
mark, that in this case again he has made himself no observa- 
tions, nor even on Vesuvius, of which alone he speaks; for he 
says that he had received his information from a correspondent 
at Naples. But besides, the only fact on which he has built his 
whole system, is that saline substance, of which even the parti- 
culars that he relates are either not wel! expressed, or must’ 
proceed from a very inaccurate observer. I shall prove hereafter - 
that this account is erroneous ; but I must first state the nature 
of volcanoes, on which all their phenomena depend. 
What are volcanic eminences ? In what manner do they he- 
gin to be produced? How do they increase in height and ex- 
tent? Fortunately the answer to these questions is obtained 
from a known event, transmitted to us by witnesses of the whole 
process, from beginning to end, in the formation of a new vol- 
canic eminence between Naples and Puzzoli, which has retained: 
the name of Aonte Nuovo (new mount), Ihave given the 
whole account of the event from those witnesses; in p. 398 
of the xith volume of my work, Histoire de la "Terre et de 
l’ Homme, of which account the following is a translation. 
“‘In the night between the 29th and the 30th of September 
1538, after two years of almost contiaual earthquakes, and es- 
pecially after a day when the earth had been continually agitated, 
at last an opening was produced in a very fertile land; through 
which opening came out so much fire, and such a quantity of 
stones and cinders, that they produced a small mountain, now 
called Monte Nuovo ; it destroyed many houses, fields, men and 
eattle, and buried under its materials the borough of Ripercola : 
it is about three miles in circumference, and its height is not 
much less than that of Mount Barbaro near it, which is esti-s 
mated at a thousand steps; the ejections from that opening ex~ 
tended down to the sea. At the suminit of this mount is stilk 
seen the mouth which ejected such a quantity of matter; which 
ejection however ceased very soon. The Lago lucrino, thus 
called from the ducre or profit reselting from an abundant . 
fishery, was so much filled up by the matters thrown out of that 
opening, that it is now only a marsh covered with reeds.” 
From this known and well circumstantiated event, we are en= 
abled to answer the» above important questions conterning the 
formation of volcanic cones. A first explosion produces an open- 
ing in the mineral sirata of the land; through that openmg 
come 
