34^ On the Caufe of 'Earthquakes. 



17. The water barometer eftabliflied in my great nicteoi 

 rograph indicated on that day a depreffion of two inches eight 

 lines : in general, it fell only two inches during the greattft 

 variations. 



18. The ftorm experienced throughout the whole iflarid of 

 St. Domingo in 1788, proceeded alio from the mountain De 

 la Charboniere. This I afcertained in the following manner: 

 A few days afier the ftorm, having made a tour through the 

 ifland on a particular million, I faw in every place where I 

 paffed that the trees overturned bv the hurricane were lying 

 in the diredlion of radii proceeding from the fummit of the 

 mountain to the different places which I vifited, though al- 

 moft all dlftant from its bale 15, 20, and 30 leagues. 



As certain winds occafion rain, whde others occafion 

 drought, it will be neceirary that I Ihould mention their 

 meteorological efie6ts, to be able to judge of the influence 

 which they have on earthquakes and volcanoes. 



19. It is well known that when two contiguous parts of 

 the atmofphere are of difierent denfities, the denfeft part, 

 which confequently has the greateft elafticity, moves to- 

 wards that which has the lefs, forming a current of air, 

 which extends towards the fide where there is the lead re- 

 li [lance. 



20. The current of the trade winds at fea follows the 

 courfe of the fun ; but it changes its dirc6lion near iflands 

 and continents. 



31. The eadern part of the ifland of St. Domingo receives 

 the trade wind without changing its direction. 



22. The whole north coait of the fame ifland changes the 

 direction of the trade wind; and, inftead of fuffering it to 

 continue its natural courfe to the weft, attrafts it, and makes 

 it incline towards the land, to form a compound current pro- 

 ceeding from north-eaft to fouth-weft. 



23. The weftern part, from Port a Piment to Port au 

 Prince, attrafts the air of the weft towards the eaft, in a di- 

 redion altogether contrary to the trade wind, and to that of 

 the eaftern part, or of Samana. 



24. The fouthcrn part of the fame ifland attracts the trade 

 Avind, and makes it change its natural direftion from eaft to 

 well, to form a current ot air proceeding from foulh-eaft to 

 north -weft. 



23. All changes which take place in regard to the current 

 of the trade winds arife, in all probability, from the fun dart- 

 ing his rays in the folid parts of the ifland, which imbibe 

 them ill the ratio of their denfities, and even of their colours. 



25. All 



