Mr Lawson on the Trade-Winds at Barbadoes. 135 



The observations in May were made from 7 to 8 P.M. ; those 

 in October from noon to 1 P.M. On this account, the tempera- 

 tures during the former will be, strictly speaking, lower than 

 they should be, in order to compare them with those during 

 the latter ; but the correction necessary to reduce them to that 

 of mid-day is so small, that it may be disregarded. Consider- 

 able and abrupt variations occur in the temperature of the 

 sea near the line, about 20" W. longitude, which are un- 

 doubtedly occasioned by the currents which meet in that 

 neighbourhood ; for on each side of this locality, as far as the 

 tropics, the temperature diminishes with tolerable regularity. 

 By the above table, the surface of the. sea through the whole 

 course of the NE. trade, seems to have increased in tempera- 

 ture between May and October by upwards of 5° Fahrenheit, 

 while that in the course of the SE. trade was diminished in 

 the same time by about 4° Fahrenheit. The positions of the 

 equatorial limits of the trades correspond very accurately with 

 those in Horsburgh's table. 



6. The temperature of the sea near Barbadoes, according 

 to some observations of my own made on my passage out in 

 March 1841, was as below. These observations were made at 

 noon ; they have been corrected for the errors of the ther- 

 mometer, and may be depended on to about 0.1° Fahrenheit. 



The sudden increase of the temperature of the sea water on 

 the Slst, and which remained pretty constant at Barbadoes 

 during the month of April, was caused by the equatorial cur- 

 rent, which, being directed to the NW. by the coast of South 

 America, flows past Barbadoes, its northern margin being con- 

 siderably to the north-east of the island. 



7. The temperature of this current increases considerably 



