I am not sensible of any real objection against our _hypothesis_, but this, being the _eleventh_ of my positions, or circumstances. It seems true, that earthquakes are more frequent in _Italy_, near _Vesuvius_, and by _Ætna_, in _Sicily_. And the cause seems apparently owing to these vulcano's. At first sight, every one would think so, but not from the true reason. This has given the great prejudice to the judgments of the curious, even at this day. But consider the matter impartially, and it will appear, so far from being a strong argument in favour of subterraneous eruptions, that it ought to be esteem'd a convincing proof to the contrary, and most cogent in favour of my principle. In strictest logic, there is no inference to be made from particulars to generals. Quite the contrary. We have but these two or three vulcano's on one quarter of the globe, and two of them toward the warmer climate of it; whereas earthquakes are innumerable, especially in those of a warmer clime. That there are no vulcano's, no discharges of fire and smoke for a continuance, and abundance, after earthquakes; no suspicion of it either from sight or smell, as we know by innumerable examples, as well as in our own country, and experience: is demonstration, that this is not the cause. If the vulcano's were the real cause of earthquakes, we ought assuredly to expect, that in the countries thereabouts, the earthquakes ought to be far more extensive than those in other countries, where are no vulcano's; but this is altogether contrary to experience. For, as the celebrated naturalist _Buffon_ observes, such are not extensive, as are near _Ætna_ and _Vesuvius_. He further adds: _Histoire naturelle_, tom. I. p. 508. speaking, among many others, of a _vulcano_ in the island of _Ternate_, he remarks, "That this burning gulph is less agitated when the air is calm, and the season mild, than in storms and hurricanes;" and says, "This confirms what I have said in my foregoing discourse, and seems evidently to prove, that the fire which makes _vulcano's_ comes not from the bottom of mountains, but from the tops, or at least from a very little depth; and that the hearth (or floor) of the fire is not far from the summit of the _vulcano's_; for, if this was not the case, great winds could not contribute to their conflagration." And this, in general, is a corroborative proof of my whole hypothesis. For there can be no great fire in the earth, where there is no great conveyance of air.