424 THE PHYSICAL GEOGRAPHY OF THE SEA. 



side. Now imagine yourself on the other side, that is, that you 

 are in the northwest quadrant, and that the storm is traveling due 

 north as before ; the vortex will pass east of you, when the wind 

 should have changed from N.E. to north, turning against the 

 hands of a watch ; but when the wind is north, it is, in the case 

 supposed, traveling south at the rate of 20 miles an hour around 

 the storm, while the progressive movement of the storm itself is 

 north at the rate of 20 miles an hour. One motion exactly can- 

 cels the other, and there is, therefore, a line of calm and light, or 

 moderate or not so heavy winds on one side of the centre, while 

 on the other side there is a line of maximum violence ; in other 

 words, in every traveling cyclone the wind blows harder on one 

 side than the other. This is the case in both hemispheres ; and 

 by handling these moving diagrams for illustration, the navigator 

 will soon become familiar with the various problems for determin- 

 ing the direction of the vortex, the course it is traveling, its dis- 

 tance, etc. Therefore, w^hen it is optional with the navigator to 

 pass the storm on either side, he should avoid the heavy side. 

 These remarks apply to both hemispheres. 



793. Captain Toynbee asks if it rains more in one quarter of a 

 The rainy quadrant of cy clouc than auothcr ? lu cycloucs that travel fast, 

 a cyclone. J supposc thcrc would bc most rain in the after quar- 

 ter; with those that have little or no progressive motion,! conjec- 

 ture that the rainy quarter, if there be one, would depend upon 

 the quarter whence that wind comes that brings most rain. The 

 rain in a cyclone is supposed to come from the moisture of that 

 air which has blown its round and gone up in the vortex ; there it 

 expands, grows cool, and condenses its vapor, which spreads out 

 at top like a great mushroom in the air, the liberated heat adding 

 fury to the storm. 



794. Such, briefly stated, are the two theories. They appear 

 Erroneous theories, to mc, from such obscrvatiou and study as I have 



been able to bestow, to be neither of them wholly right or alto- 

 o-ether wrong. Both are instructive, and the suggestions of one 

 will, in many instances, throw light upon the facts of the other. 

 That rotary storms do frequently occur at sea we know, for ves- 

 sels have sometimes, while scudding before the wind in them, 

 sailed round and round. The United States brig " Perry" did 

 this a few3^ears ago in the West Indies; and so did the "Charles 



