146 Mr Lawson on the Trade-Winds at Barbadoes. 



regular trade, which is usually less marked in these respects ; 

 and, at Barbadoes, it was usually found to be above both the 

 trade and the south-easterly current described above. Such 

 seems to be the origin of the north-westerly and south-westerly 

 currents which are seen within the range of the trade-winds, on 

 either side of the line respectively, and which, it will be 

 readily understood, have a very important bearing on the sub- 

 ject of the storms of these latitudes. 



26. These north-westerly currents in the atmosphere were 

 perceived at Barbadoes, both when the moon had her greatest 

 northern or southern declination, and when she was in the in- 

 termediate points, and therefore seemed to be quite independ- 

 ent of her position with regard to the equator. Although 

 not observed very often, still that does not disprove their fre- 

 quent existence. This opinion is corroborated by the fact 

 that, when the equatorial current could be distinguished by 

 the drift of a free cirri or cirro-strati, these usually presented 

 the characters of a cymoid cirro-stratus, that is, a group elon- 

 gated in the line of drift, but the separate portions of which 

 were in lines almost perpendicular to that direction, clearly 

 indicating the existence of the crossing current which led to 

 its formation. 



27. On a few occasions the north-westei'ly current was directed 

 downwards to the earth's surface, and on one, the 30th August, 

 formed a strong breeze from that point. During the two pre- 

 vious days the wind had been very slight, varying from ENE. 

 to SSE ; the moon's declination on the upper meridian in the 

 same time decreased from 20 S. to 11 S., her hour of transit 

 being delayed from 9^' 52™ P.M. to ll** 20"^. Under these 

 circumstances, the inner margin of the trade being evidently 

 to the northward of Barbadoes, as the moon approached the 

 meridian on the evening of the 30th August, causing a par- 

 tial flow of the quiescent air over the earth's surface to the 

 southward, the north-westerly current (of which there had been 

 no pi'evious trace that day) fell downwards to supply its place, 

 and at 9 P.M. was experienced as a strong NW. wind. It is 

 worthy of remark too, that, while the wind below was NW., 

 a current from the SE. was flowing rapidly above. During 



