I?52 Professor^ Kaemtz on the more important 



wind is generally met with, while below, the trade-wind blows 

 with regularity. The existence of the west wind in the upper 

 strata of the air is further proved by the following fact : — In 

 the island of Barbadoes, which lies on the eastern edge of the 

 Antilles, the inhabitants, while the usual trade-wind was blow- 

 ing, were not a little astonished at volcanic ashes being brought 

 by it. Some time afterwards they heard that these were de- 

 rived from the volcano situated on the island of St Vincent, 

 which is to the west. These ashes had undoubtedly been 

 transported in the upper strata of the atmosphere beyond Bar- 

 Imdoes, and during their descent had again come into the region 

 of the trade-wind. 



But not only do the trade- winds prove the production of 

 winds by differences of temperature in different places ; the 

 monsoons also in the Indian Sea, as well as the north winds, 

 which, especially during summer, blow in the Mediterranean 

 Sea and on the north coast of Africa, afford the most satisfac- 

 tory evidence of the accuracy of this view of the subject. 



Winds in High and Low Latitudes. — The polar boun- 

 daries of the trade- wind lie in a latitude of from 20° to 30° ; 

 a few degrees nearer the pole we find chiefly south-west 

 winds in the northern, and north-west winds in the southern 

 hemisphere. And although these are much more frequent 

 than any other winds, yet they do not blow so regularly as 

 the trade-winds. This prevalence of westerly winds in middle 

 latitudes is proved more particularly by the circumstance 

 that, according to the average of several years, the packets 

 from Liverpool to New York are forty days on the passage, 

 whereas the voyage back again is accomplished in twenty-three 

 days. If we remove further from the equator, the south-west- 

 erly winds remain, it is true, still the prevaihng ones, but their 

 frequency seems to diminish. According to the facts collected 

 by Dove, Schouw, and myself, all places in high latitudes pre- 

 sent a preponderance of south-westerly winds, and wherever 

 particular points exhibit a deviation from this law, we must 

 seek for the cause in local circumstances. This south-west wind 

 is nothing more than the descending wind of the upper regions, 

 which now spreads itself more widely on the surface of the earth. 



We find great variableness of the wind in these high lati- 

 tudes, and it seldom happens that it blows from the same di- 



