STORMS, HURRICANES, AND TYPHOONS. 



419 



to the north of her, as at C, where the air ascends as fast as it 

 comes pouring in from all sides. The ship, let it be supposed, is 

 just on the verge of, but exterior to the vortex, or that place 

 where the wind commences to revolve. The first rush of the air 

 at a will be directly for the centre C ; consequently, a ship so 



placed would report the storm as commencing with the wind at 

 south. For the sake of illustration, we will suppose this place of 

 low barometer to be stationary, and the air, as it rushes in, to 

 ascend at the disc C. Thus the area of inrushins; air will 

 gradually enlarge itself by broad spreading, like a circle on the 

 water, until it be compassed by a circle with a radius C S, of 

 indefinite length. The air then, on the meridian SON, but to 

 the south of a, will not blow along this meridian and pass over 

 the ship ; in consequence of the diurnal rotation of the earth, it 

 will take a direction, S a', to the westward ; and the arrow d a, 

 representing a S.S.E. wind, will now show the direction of the 

 wind at a. Thus the ship will report that the wind commenced 

 at south, and gradually hauled to S.S.E., i.e. against the hands of 

 a watch ; and so the arrows h' a' will represent the direction of 

 the wind at each station, a' a' a\ when the storm commenced, 

 and the arrows cV a' the directions afterwards, thus showing it to 

 have veered against the hands of a watch. And this is the 

 direction in which the forces of diurnal rotation, when not 



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