TRADE-WINDS OF THE SOUTHERN HEMISPHERE. 353 



be electricity tliat is concerned in it ; but because we can not de- 

 tect tliem, that is no proof of their non-existence. If there be a 

 crossing, there is a power to guide the air through its mazes ; for, 

 relj upon it, the wind in its circuit is left no more to chance than 

 is the earth in its orbit. There are forces- to restrain each and to 

 keep it within its limits. 



4th. Ehrenberg's discoveries with the microscope: In the sea 

 dust and red fogs of the North Atlantic he recognizes organisms 

 from South America. This dust has been collected for his mi- 

 croscope on the polar side of the northeast trades, and the infer- 

 ence is, that it was conveyed first to the equatorial calm belt by 

 the surface wind, and was carried thence to the calms of Cancer 

 by the upper currents. 



Thus this hypothesis concerning the crossing at the calm belts, 

 and the flowing of the air over from one" hemisphere to the oth- 

 er, seems to be consistent with aU the facts and circumstances men- 

 tioned in 1, 2, 3, and 4. 



So far, however, the evidence seemed more specific touching 

 the crossings at the equatorial calm belt than at the tropical. 

 The vapor that is brought over into the northern hemisphere is 

 probably taken up by the southeast trade-winds. This suppo- 

 sition and Ehrenberg's "talhes" to the wind, as his sea dust has 

 been called, suggest the idea of a crossing at the calms of Cancer. 

 But the circumstances going to show the crossing at the calms of 

 Capricorn did not amount to evidence ; the crossing was only in- 

 ference drawn by analogy. 



1004. My own observations, and the experience of mariners 

 who are acting as observers in these researches touching sea and 

 air, show that the westerly winds which blow counter to the 

 trades on the polar side of the tropical calms are much more 

 steady, strong, and constant in the southern than in the northern 

 hemisphere. 



The former have won for themselves, among mariners, the 

 name of the "brave west winds" of the extra-tropical south. 

 They are quite as constant from the west as in the North At- 

 lantic the trades are from the east. Sailing with them to and 

 from. Australia, ships under canvas alone have attained a speed 

 and accomplished runs which steam has never enabled any ves- 

 sel to reach. In two months' time and less, sailing vessels have 



