288 



THE ATMOSPHEEE AND METEOEOLOGY. 



descends obliquely towards the surface of the sea, and being com- 

 pressed to the right by the trade-winds, it continues to advance 

 towards the north-west. Arriving outside the tropics, the hurricane 

 is no longer under the lateral pressure of the north-east wind ; it has 

 a free path before it, and under the influence of the earth's rotation, 

 it bends with a graceful curve in a northerly direction, then in that 

 of the north-east. At the same time, the storm which has just en- 

 tered the temperate zone gradually enlarges the diameter of its spirals, 

 and consequently loses its violence in proportion as it advances to- 

 wards the pole. Thus the hurricane of 1839, whose breadth was 

 about 300 miles, when it crossed the Antilles, extended to 500 miles 





Ay^ 



/ 



Fig. 116 —Simultaneous Cyclones experienced at Reunion, December, 1824. 



