432 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOROLOGY. 



chambers of tlie upper air the office which the jet of cold water does 

 for the exhausted steam in the condenser of the engine. The pre- 

 sence of land, not water, about this south polar stopping-place is 

 therefore suggested ; for the sea is not so favourable as the moun- 

 tains are for aqueous condensation. 



835. By the terms in which our proposition has been stated, and 

 The topographical bv the manner in which the demonstration has been 



features of the aat- titii -ji l f • n 



arctic bands. couductod, the prcscnce m the antarctic regions oi 



land in large masses is called for ; and if we imagine this land to be 

 relieved by high mountains and lofty peaks, we shall have in the 

 antarctic continent a most active and powerful condenser. If, 

 again, we tax imagination a little farther, we may, vnthout trans- 

 cending the limits of legitimate speculation, invest that unexplored 

 land with numerous and active volcanoes. If we suppose this also 

 to be the case, then we certainly shall be at no loss for sources of 

 dynamical force sufficient to give that freshness and vigour to the 

 atmospherical cu'culations which observations have abundantly 

 shown to be peculiar to the southern hemisphere. Neither under 

 such physical aspects need it be any longer considered paradoxical 

 to ascribe the polar tendency of the " brave west winds " to rare- 

 faction by heat in the antarctic circle. This heat is relative, and 

 though it be imparted to air far below the freezing-point, raising its 

 temperature only a few degrees, its expansive power for that change 

 is as great when those few degrees are low down as it is when they 

 are high up on the scale. If such condensation of vapour do take 

 place, then hberation of heat and expansion of air must follow, and 

 consequently the oblateness of the atmospherical covering of our 

 planet will be altered ; the flattening about the poles wiU be reheved 

 by the intumescence of the expanded and ascending air, which, 

 protruding above the general level of the aerial ocean, will receive 

 an impulse equatorially, as well from the mere derangement of 

 equihbrium as h'om the centrifugal forces of the revolving globe. 

 And so this air, having parted with its moisture, and having re- 

 ceived the expansive force of aU the latent heat evolved in the process 

 of vaporous condensation, wiU commence its return towards the 

 equator as an upper current of dry air. 



836. Arrived at this point of the investigation, we may con- 

 A perpetual cyclone, template the wholc system of these "brave west 

 winds " in the light of an everlasting cyclone on a gigantic scale. 

 The antarctic continent is in its vortex, about which the wind, in 

 the great atmospherical ocean all around the world, from the pole 



