Mr Lawson on (he Trade-Winds of Batbadoes. 375 



rent, which, then gliding above those flowing to the south- 

 wardj will reassume its ordinary level in the atmosphere. 



66. Though it was advisable, for the sake of clearness, to 

 assume that the points of junction with the central edge of 

 each current (47) of the portion of that current which hdd 

 been drawn towards the line of least pressure, viz. of that 

 from E. with the north-easterly current, of the N. with the 

 north-westerly current, and of the W. with the south-westerly, 

 were situate round a common centre, it does not by any 

 means follow that they are so in reality ; in fact, it would 

 appear the point in the trade-wind precedes the others to the 

 westward, and that these follow, varying in relative position 

 according to circumstances. 



QQ» From what has been stated, it will be clear that were 

 an observer so placed that the centre of the storm should 

 pass over him, he would find the barometer begin to fall as 

 tlie upper portions of the trade-wind, and the NW. current, 

 immediately over him, became accelerated in their com'se 

 (52); and as the storm nioved westward and the central 

 margin (65) of the trade-wind reached him^ the fall of the 

 barometer would continue. When the north-easterly cur- 

 rent ceased, he would experience a variable period of calm^ 

 with occasional severe gusts from NE. or NW. and the in- 

 termediate points (60), after which the NW. current would 

 suddenly commence With great violence. As the central 

 margin of the NW. current approached the observer, the 

 barometer would continue to fall, and on its reaching him 

 would obtain its minimum, at which it would remain with 

 calm weather, occasionally interrupted by gusts, between 

 NW. and SW., until the arrival of the central edge of the 

 SW. current, when the wind would suddenly back round to 

 the W. WSW. or SW;, and it would gradually riscj until the 

 air along the earth's surface insinuating itself under the east- 

 ern part of the South-western current (64), and raising this 

 in the atmosphere, would lead to the re-establishment of 

 the trade-wind under it, and restore the full atmospheric 

 pressure. 



67. Thus the fall of the barometer is caused by the gi*adual 

 removal of the NE. and NW. currents from above the ob- 



