168 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOROLOGY. 



"AViXDS OF THE Northern Hemisphere," arrives by dediiction 

 at a like conclusion. In that paper he has discussed the records 

 at no less than five hundred and seventy-nine meteorological 

 stations, embracing a totality of observations for two thousand eight 

 hundred and twenty-nine years. He places his "meteorological 

 pole " — pole of the winds — near latitude 84° north, longitude 105° 

 west. The pole of maximum cold, by another school of philo- 

 sophers, 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' w^est. Neither of these poles is a point suscej)tible of 

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

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

 jDoles are areas or discs, not points, it is a little cmious that philo- 

 sophers in different parts of the world, using different 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 position 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 

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

 knowledge, w^here we pause and linger, fondly hoping that the 

 chambers of hidden things may be thrower open, and that w^e may 

 be permitted to behold and contemplate the mysteries of the wdnds, 

 the frost, and the trembling needle. In the polar calms there is 

 (§215) an ascent of air ; if an ascent, a diminution of pressure 

 and an expansion ; and if expansion, a decrease of temperatm^e. 

 Therefore we have pahpably enough a connecting link here between 

 the polar calms and the polar place of maximum cold. Thus we 

 establish a relation between the pole of the winds and the pole 

 of cold, with evident indications that there is also a physical 

 connection between these and the magnetic pole. Here the out- 

 croppings of a relation between magnetism and the circulation of 

 the atmosphere again appear. 



362. Thousands of observations, made by mariners and recorded 

 Thfi barometer in the in their abstract logs, have enabled us to determine 

 ^■ind bands. approximately the mean height of the barometer 



for the various bands (§ 352) at sea. Between the parallels 



* Gauss. 



