(•CO J A M A I C; A. 



jartlcuhub relative to tl'je trade and land-wind?, whlcli h.avc a great 

 influence on the thermcmeter in this country. 



SECT. II. 



Trade and Land-Winds. 



Doctor Halley, I believe, %vas the firfl wlio communicated 

 a rational explication of the caufes of the trade, or as it is called here, 

 the fea-breeze, which blows all the year between the Tropics. 

 Dr. Franklin ftruck out lately a very ingenious theory, fomewhat 

 different from the former ; and has endeavoured to make it ?.ccount 

 for the periodical North- Wefters, which predominate in the higher 

 latitudes of North-America. It would -employ too much room to 

 tranfcribe what thefe learned gentlemen .have publifhed. I fhall 

 therefore confine mylelf to fuch remarks as occurred to me at 

 Jamaica, not without hope that they may lerve to throw Ibnie 

 further light on a fubjefl, which has not only been thought ex- 

 tremely curious and interefting, but to be ranked among thofe 

 difpenfations which are the evident refult of Infinite Wifdom and 

 Goodnefs. 



A chain of hills running N. and S., of which there are many in 

 this ifland, will, by the interruption they give to the free and dire£t 

 courfe of the fea-breeze, render all places near, lying to the Weft- 

 ward of them, hotter than other places which are ventilated without 

 fuch obflrudions. Neverthelefs, the regular breeze, if it blows 

 not very violent, is liable to be frequently defleded from the Ihore 

 by the land-wind ; which latter is often fuddcnly produced after the 

 tailing of heavy fliowers inland, and upon the mountains ; the cool 

 vapour rufhes from thence towards the hot, dry air, which hovers 

 over the favannalis and coafts adjacent. The great action, or 

 rarefadlion, caufed by the fun in this climate, regularly attrads a 

 train of vapour, or dcnfe air, after it, and by tb.at means gives birth 

 to the diurnal breeze, which is light and gentle at firft in the 

 ;morning, increafes as the fun afccnds higher above the horizon, 

 and declining in the fame gradual manner, for the moft part, as 

 the fun dcfcends in the afternoon. 



The 



