710 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. 



we know only some of the links. I have found lavas exactly like that of Ve- 

 suvius in the whole way from Florence to Naples, and in places where there was 

 no suspicion of volcanos. All the lakes of Italy, which I have seen hitherto, 

 exhibit traces, not to say evidences, of this. 



I begin to think that the whole earth is perhaps in the same case with its 

 surface, and was thrown into the utmost disorder at some period of time, of 

 which no remembrance has been preserved. Lazzaro Moro, a Venetian, has 

 gone much further than I do : all the mountains, isles, and continents arose, 

 according to him, from the bottom of the sea, by means of subterraneous fires. 

 I never heard of his opinion till after I had formed my own conjecture, or rather 

 verified the fact in part of the Apennine which I have passed through. I have 

 had time only to run over the titles of his chapters. 



CIK. On the Currents of Sea at the Antilles. By Dr. Peyssonnel, F.R.S. p. 624. 



The coasts of these American islands are subject to counter-tides, or extraor- 

 dinary currents, which render it very dangerous to chaloupes and other small 

 craft to land ; while at the same time the boats and ships in the roads are 

 scarcely ever sensible of them, and seldom incommoded by them ; nor do those 

 which are out at sea appear to be affected by them. It is however certain that 

 a regular wind constantly blows, in these parts of the torrid zone, from the tropic 

 of Cancer, to the equinoctial line, from the east ; inclining sometimes northward, 

 and sometimes southward. This wind is called alize, or trade-wind, for reasons 

 admitted by philosophers, and it draws the water westward, giving a total and uni- 

 form course to that immense quantity, which comes from the great river of the 

 Amazons, and from an infinite number of other rivers, which discharge them- 

 selves into the ocean. These currents passing to the westward, go up to the 

 American islands, then to the coasts of Jucatan and Mexico, and running round 

 in the gulf, return Into the great ocean, by the straits of Bahama, along the 

 coasts of Florida, in order to pursue, in the north, the course ordained them by 

 the Supreme Being. It is in this course the waters are known to nm with an 

 extraordinary rapidity ; they pass between the great and little islands of America, 

 in the great deeps, by an almost even and imperceptible motion ; but against the 

 shores and coasts of these islands, which form this archipelago, these currents 

 are very sensible and dangerous; they interrupt the navigation, insomuch that it 

 is scarcely possible to stem these tides to get to the eastward. 



It often happens, that vessels steering from St. Domingo, or the other Lee- 

 ward islands, to the windward ones, cannot absolutely accomplish it, and are 

 therefore obliged to get out of the channel, and steer away to the northward, in 

 order to tack up to the windward isles. These are daily observations, and well 

 known to all navigators of America. 



Besides these regular currents, there are others, called counter-tides, which 



