Mr Lawson on the Trade-Winds at Barbadoes. 147 



the night the north-westerly wind disappeared, and next morn- 

 ing, at 5 A.M., there was only a gentle breeze from the NE. 



28. Between the equatorial margins of the trades, in the 

 Atlantic, the wind, according to Horsburgh, is variable, but 

 mostly from the SW. A similar, but more decided disposi- 

 tion of the winds, is observed in the Indian Ocean, in which, 

 during what is called the westerly line monsoon, the winds 

 from the equator to lat. 10° or 12° S, or the space between 

 the equatorial limit of the NE. monsoon to the N., and 

 the SE. trade to the south of the line, flow from the W., 

 NAV., or NNW. At Barbadoes the same tendency was ob- 

 served on several occasions. On the 9th of September, the 

 moon's declination being 27° N., and her hour of transit 6^ 

 33™ A.M., and the sun's declination about 5° N., there was a 

 fine breeze from SE. and SSE. at 5 and 9 A.M. respectively, 

 which gradually died away towards noon. The sky at 9 A.M. 

 was perfectly overcast, and continued so during the day. The 

 equatorial margin of the trade was evidently to the northward 

 of the island. Under these circumstances, about mid-day the 

 barometer began to fall rapidly, so much so, that a hurricane 

 was expected. At 1 P.M. a slight breeze sprung up from 

 SSW., and a very heavy sea began to run into Carlisle Bay, 

 clearly shewing that a fresh breeze from the same point had 

 prevailed at sea, a short distance from the island. 



29. The immediate cause of the fall of the barometer in this 

 instance, seems to have been the following : The moon having 

 passed the meridian at &^ 33°i A.M., with a high northern de- 

 clination, produced a brisk breeze from the SE. or SSE., 

 which, as the sun approached the meridian, gradually declined. 

 The sun's declination was then 5° N., and the point to which 

 both his attraction and calorific effect, tended to clear the at- 

 mosphere, was consequently the parallel of lat. 5° N, The 

 conjoint influence gradually overcame the motion of the lower 

 portions of the atmosphere to the northward at Barbadoes ; 

 but, before their motion could be reversed, it was necessary 

 both that those portions lying between lat. 5° N. and the la- 

 titude of Barbadoes (13° N.) should be drawn to the south- 

 ward, and that sufficient time be given for the air over Bar- 



