120 THE PHYSICAL GEOGRAPHY OF THE SEA. 



tions for two thousand eight hundred and twenty-nine years. He 

 places his " meteorological pole" — pole of the winds — near lati- 

 tude 84° north, longitude 105° west. The pole of maximum cold, 

 by another school of philosophers. Sir David Brewster among 

 them, has been placed in latitude 80° north, longitude 100° west ; 

 and the magnetic pole, by still another school,* in latitude 73° 35^ 

 north, longitude 95° 39^ west. 



223. Neither of these poles is a point susceptible of definite 

 and exact position. The polar calms are no more a point than 

 the equatorial calms are a line ; and, considering that these poles 

 are areas, not points, is it not a little curious that philosophers 

 in different parts of the world, using diiFerent data, and following 

 up investigation each through a separate and independent system 

 of research, and each aiming at the solution of different problems, 

 should nevertheless agree in assigning very nearly the same posi- 

 tion to them all ? Are these three poles grouped together by 

 chance, or by some physical cause ? By the latter, undoubtedly. 

 Here, then, we have another of those gossamer-like clews, that 

 sometimes seem almost palpable enough for the mind, in its hap- 

 piest mood, to lay hold of, and follow up to the very portals of 

 knowledge, where pausing to knock, we may boldly demand that 

 the chambers of hidden things be thrown wide open, that we may 

 see and understand the mysteries of the winds, the frost, and the 

 trembling needle. 



224. In the polar calms there is (§ 113) an ascent of air ; if an 

 ascent, a diminution of pressure and an expansion ; and if expan- 

 sion, a decrease of temperature. Therefore we have palpably 

 enough a connecting link here between the polar calms and the 

 polar place of maximum cold. Thus we establish a relation be- 

 tween the pole of the winds and the pole of cold, with evident in- 

 dications that there is also a physical connection between these and 

 the magnetic pole. Here the outcroppings of the relation between 

 magnetism and the circulation of the atmosphere again appear. 



May we not find in such evidence as this, threads, attenuated 

 ctnd almost air drawn though they be when taken singly and alone, 

 yet nevertheless proving, when brought together, to have a cour 

 sistency sufficient, with the lights of reason, to guide us as we seek 

 to trace the wind in his circuits? The winds (§ 106) approach 



* Gauss. 



