482 MR MILNE ON TWO STORMS WHICH SWEPT OVER 



tion of the strongest cuiTent. The NE. wind liowing from the North Pole would, 

 whilst in contact with the SW. wind, which is also as constantly flowing, must 

 produce eddies of large extent, and violent in proportion to the strength of the 

 opposing winds. So far, we see, if these eddies are the true cause of gvi'ator>' 

 storms, why they should have both a progressive and rotatory motion. Why these 

 circles should always advance towards the north is not so clear, — for this would 

 imply that the southerly wind always obtained the mastery. Nor is it equally 

 clear why these stormy circles should, as Colonel Reid also alleges, revolve in a 

 manner contrary to the hands of a watch, — for this would imply that the southerly 

 wind always flows on the east side of the northerly current. On the west side of 

 the Atlantic Ocean, this last assumption is at least not improbable, as the Gulf- 

 stream, in its progress northwards, will generally carry alongst with it an at- 

 mospheric current, whilst the continent of North America is as natural a conduc- 

 tor of cold winds flowing in an opposite direction. In this way, perhaps, an ex- 

 planation may be found of the fact, that storms generated in the Atlantic, and 

 impinging on the British islands, take a north or north-easterly direction, and 

 rotate always from east to west. But it may be matter of doubt, whether this 

 rule can be applied generally to the whole northern hemisphere, in the way 

 Colonel Reid proposes. 



Nor should it be taken for granted, that the axis of revolution, forming the 

 nucleus of the supposed stormy circle, is produced merely by two opposite aerial 

 currents acting on each other. It is possible, that this very simple solution of the 

 problem may be the correct one, and that electricity and other active forces which 

 generally accompany storms are ejects rather than causes. But the only method 

 of arriving at certainty on this point, is l^y precise and extensive observation. 



It will be observed, with what remarkable regularity the depression of the 

 barometer, during the gale last above described, diminished towards the west- 

 ward. The lines or bands of equal depression, of which ten have been given in 

 the foregoing table, are all parallel, or very nearly so, to each other, and have evi- 

 dently the same direction as that taken by the storm itself in its progress north- 

 wards. 



That the barometer should be lowest at those places situated nearest to the 

 centre of the storm, appears to be not only quite consistent with the principles 

 before explained, but to be unintelligible on any other assumption. The explana- 

 tion most generally given of the fall of the barometer during a gale, is, that the 

 air, when put into rapid motion over the surface of the globe, necessarily acquires 

 a centrifugal tendency. Now, on the assumption that the outer bands of wind 

 in the stormy circle revolve in the same time with the inner bands, the velocity 

 of the former being in that case greater, their centrifugal force ought also to be 

 greatest, so that the barometer would fall more in the outskirts than near the 

 centre of the storm, — a result which, as we have seen, would be inconsistent with 



