LAND AND SEA BEEEZES. 259 



CHAPTER YII. 



LAND AND SEA BREEZES. — WINDS FEOM THE MOUNTAINS. — SOLAE BEEEZES. — LOCAL 

 WINDS. — THE SIMOON, SCIEOCCO, F(EHN, TEMPESTS, AND MISTEAL. 



Beside the lateral deviations which occur twice in the year, the 

 trade- winds are subject along the coasts to rapid daily deviations. 

 The whole outline of the continents is bordered, so to speak, with a 

 fringe of breezes produced by the difference of temperature between 

 the land and the water. During the day the countries of the coast- 

 line are heated much more rapidly than the surface of the ocean. 

 Towards ten o'clock in the morning, after a shorter or longer period 

 of calm, a rupture of the equilibrium occurs between the aerial 

 masses, and the fresher atmosphere reposing above the waters tends 

 towards the land, there to replace the expended air which rises into 

 the higher regions. Little by little this movement of translation, 

 which at first only made itself felt in the neighbourhood of the coast, 

 communicates itself to all the surrounding atmospheric strata, and 

 soon the breeze moving nearer and nearer through the ocean of air, 

 occupies a tolerabl}^ large space above the sea and the continent, 

 which it unites as an iron plate unites the two branches of a magnet. 

 During the night the ground loses by radiation a great part of the 

 heat that it had received, while the sea preserves pretty nearly the 

 temperature of the day. The equilibrium is again disturbed, but it 

 is now in the direction of the sea ; the breeze is brought back, and 

 blows in the opposite way. It is thus that in the space of 24 hours 

 the breeze oscillates from land to sea, and from sea to land, by a motion 

 of ebb and flow, analogous to that of the tides. In the countries of 

 La Plata these alternate breezes from land and sea present such a 

 regularity that they have received the name of firazones (gyrations). 

 Around Otaheite they also succeed each other with such punctuality 

 that a vessel could for several consecutive nights make the tour of the 

 island, and always with the w4nd behind it. 



These breezes, which one might also call daily monsoons, co-exist 

 with the movement of the trade-winds, and are in consequence carried 



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