THE WINDS. 217 



CHAPTER XIIL 



THE WINDS. 



Plate YIIL, ^ 461. — Monsoons, 462.— Why the Belt of Southeast is broader than the 

 Belt of Northeast Trade-winds, 463. — Effect of Deserts upon the Trade-winds, 466. 

 — At Sea the Laws of Atmospherical Circulation are better developed, 470. — R.vin 

 WixDs : Precipitation on Land greater than Evaporation, 472. — The Place of Sup- 

 ply for the Vapors that feed the Amazon with Rains, 473. — Monsoons : How 

 formed, 474. — Monsoons of the Indian Ocean, 475. — How caused, 476. — How the 

 Monsoon Season may be known, 478, — The Distance to which the Influence of 

 Deserts upon Winds may be felt at Sea, 479. — "VVTiy there are no Monsoons in the 

 Southern Hemisphere, 482. — Why the Trade-wind Zones are not stationary, 483. 

 Thk Calm Belts : Doldrums — a Zone of constant Precipitation, 486. — The Horse 

 Latitudes, 488.— The Westerly Winds, 490. 



461. Plate YIIL is a chart of the wmds, based on information 

 derived from the Pilot Charts, one of the series of Maury's Wind 

 and Current Charts. The object of this chart is to make the stu- 

 dent acquainted with the prevailing direction of the wind in every 

 part of the ocean. 



The arrows of the plate are supposed to fly with the wind ; the 

 half bearded and half feathered arrows denoting monsoons or pe- 

 riodic winds ; the dotted bands, the regions of calm and baffling 

 winds. 



462. Monsoons, properly speaking, are winds which blow one 

 half of the year from one direction, and the other half from an 

 opposite, or nearly an opposite direction. 



Let us commence the study of Plate VIII. by examining the 

 trade-wind region ; that, also, is the region in which monsoons are 

 most apt to be found. 



463. The belt or zone of the southeast trade-winds is broader, 

 it will be observed, than the belt or zone of northeast trades. 

 This phenomenon is explained by the fact that there is more land 

 in the northern hemisphere, and that most of the deserts of the 

 earth — as the great deserts of Asia and Africa — are situated in the 

 rear, or behind the northeast trades ; so that, as these deserts be- 

 come more or less heated, there is a call — a pulling back, if you 



