420 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOEOLOGY. 



day. Consequently, the counter-trades of the southern hemi- 

 sphere transport in given times larger volumes of air towards the 

 south than our counter- trades do towards the north. This air re- 

 turns to the tropical calm belts as an upper current. If, descend- 

 ing there, it feeds the trade-winds, then, the supply being more 

 abundant for the S.E. trades than for the N.E,, the S.E, trades 

 must be the stronger ; and so they are ; observations prove them 

 so to be. Thus the crossing of the air at the tropical calm belts, 

 though it may not be proved, yet it is shown to be so very probable 

 that the onus of proof is shifted. It now rests with those who 

 dispute the crossing to prove their theory the true one, 



817. Arrived at this point, another view in the field of conjec- 

 Tbe waves they get up. ture is presented, which it is proper we should 

 pause to consider. The movements of the atmosphere on the 

 polar side of 40° N. are, let it be repeated, by no means so con- 

 stant from the west, nor is the strength of the westerly winds 

 there nearly so great on the average as it is in the corresponding 

 regions of the south. This fact is well known among mariners. 

 Every one who has sailed in that southern girdle of waters which 

 belt the earth on the polar side of 40°, has been struck with the 

 force and trade-like regularity of the westerly winds which pre- 

 vail there. The waves driven before these winds assume in their 

 regularity of form^ in the magnitude of their proportions, and in 

 the stateliness of their march, an aspect of majestic grandeur that 

 the billows of the sea never attain elsewhere. No such waves 

 are found in the trade-winds ; for, though the S.E. trades are quite 

 as constant, yet they have not the force to pile the water in such 

 heaps, nor to arrange the waves so orderly, nor to drive them so 

 rapidly as those "brave" mnds do. There the billow^s, chasing 

 each other like skipping hills, look, with their rounded crests 

 and deep hollows, more like mountains rollmg over a plain than 

 the waves which we are accustomed to see. Many days of con- 

 stant blowing over a wide expanse of ocean are reqmred to get 

 up such waves. It is these winds and waves which, on the voy- 

 age to and from Australia, have enabled the modern chpper-ship 

 to attain a speed, and, day after day, to accomplish runs which at 

 first were considered, even by the nautical world, as fabulous, and 

 are yet regarded by all with wonder and admiration, 



818, Seeing, therefore, that we can bring in such a variety of 

 A meteorological f^cts and circumstauces, all tending to show that the 

 corouary. gjg^ trade-winds are stronger than the N.E., and 



