362 



Mr. J. K. Laugh ton on the Theory of 



From latitude 



Mean number of days . 



Crossing thelast-named 

 latitude in west lon- 

 gitude 



45° to 35 c 

 51 



I 16° 



35° to 30° 

 3 



18°-8 



30° to 25° 

 2-5 



21°5 



This Table, giving the means of a very large number of ob- 

 servations, shows no indications of any undue delay in the lati- 

 tude where the zone of calms is laid down in the diagram. 

 Neither does the Chart published by the Board of Trade show 

 any such calms extending across the Atlantic, but represents 

 them rather as confined to the immediate neighbourhood of the 

 Western Islands. Further east, under the same latitude, we 

 find a very marked preponderance of north-easterly winds; and 

 further west, south-westerly winds seem to establish themselves, 

 even in a lower latitude. The chart shows this, and the extracts 

 of logs given in the ( Sailing Directions ' (vol. ii. pp. 156-340) 

 are witness to the same ; and the whole body of evidence points 

 to & patch, not a zone of calms in the North Atlantic. I would 

 suggest that, in conceiving such a zone, geographers have been 

 carried away by a fanciful tradition of ships becalmed for days and 

 weeks in the horse latitudes. How the traditionary story of horses 

 thrown overboard for want of water has arisen, I am unable to 

 say ; but I would call attention to the historical fact that the 

 name was originally given as denoting the boisterous and tem- 

 pestuous nature of the region which received it : this region was 

 the part of the sea in the neighbourhood of Bermuda — the " still- 

 vexed Bermoothes " of our ancestors — and was called by the old 

 Spaniards " el golfo de las yeguas" (the mare's gulf), in contra- 

 distinction to the trade -wind region, which was called "el golfo 

 de las damas" (the ladies' gulf). (Humboldt's ' Personal Nar- 

 rative,' by Williams, vol. ii. p. 8; Churchill's ' Voyages,' edit. 

 1704, vol. i. p. 658.) 



The evidence which I have thus briefly adduced seems to me 

 to lead to the conclusion that in the North Atlantic the air cir- 

 culates in a sort of enormous whirlpool, the centre or vortex of 

 which is, on the average, somewhere near the Azores, where 

 it produces what may be considered a species of atmospheric 

 Sargasso sea, and that towards the north or north-west of this 

 circle the denser air from the pole keeps up a constant pressure, 

 which bends down the south-westerly current, causing it to stream 

 more from the west and afterwards from the north-west. 



A great part of these winds, further deflected, forms the 

 northerly and north-easterly winds on the western side of Europe ; 

 but a very large portion appears to sweep over the north of the 

 Continent as far as the Ural Mountains, continuing in its east- 



