74 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS ZIETEOROLOGY. 



atmospliere ; for, as in tlie ocean (§ 201), so in tlie air, there is a 

 regular system of circulation. 



204. Before we proceed to describe this system, let us point out 

 Different belts of ^^6 principal belts or bands of wind that actual ob- 

 ^i^'i'^- servation has sho^vn to exist at sea, and which, with 



more or less distinctness of outline, extend to the land also, and 

 thus encircle the earth. If we imagine a ship to take her departure 

 from Greenland for the South Shetland Islands, she will, between 

 the parallels of 60^ north and south, cross these several bands or 

 belts of winds and cahns nearly at right angles, and in the follow- 

 ing order : (1.) At setting out she will find herself in the region 

 of south-west winds, or counter- trades of the north — called counter 

 because they blow in the du-ection whence come the trade-winds of 

 their hemisphere. (2.) After crossing 50^, and until reaching the 

 parallel of 35° N., she finds herself in the belt of westerly -^inds, a 

 region in which winds from the south-west and winds fi'om the 

 north-west contend for the mastery, and with nearly equal -persist- 

 ency. (3.) Between 35^ and 30^, she finds herself in a region of 

 variable winds and calms ; the winds blowing all around the com- 

 pass, and averaging about three months fi'om each quarter during 

 the year. Om' fancied ship is now in the " horse-latitudes." 

 Hitherto winds with westing in them have been most prevalent ; 

 but, crossing the cahn belt of Cancer, she reaches latitudes where 

 winds vfith easting become most prevalent. (4.) Crossing into 

 these, she enters the region of north-east trades, which now become 

 the prevailing winds, until she reaches the parallel of 10^ N., and 

 enters the equatorial cahn belt, w^hich, like all the other v>' ind-bands, 

 holds fluctuating limits. (5.) Crossing the parallel of 5^ N., she 

 enters where the south-east trades are the prevailing winds, and so 

 continue until the parallel of 30^ S. is reached. (6.) Here is the 

 calm belt of Capricorn, w^here, as in that of Cancer (3), she again 

 finds herself in a region of shifting ^inds, light airs, and calms, 

 and where the winds with westing in them become the prevailing 

 winds. (7.) Between the parallels of 35° and 40^ S., the north- 

 west and south-vfesfc winds contend with equal power for the mas- 

 tery. (8.) Crossing 40°, the counter-trades (1), — the north-west 

 -winds of the southern hemisphere, — become the prevailing winds, 

 and so remain, as far as om' observations at sea extend towards the 

 south pole. 



Such are the most striking movements of the winds at the sur- 

 face of the sea. But, in order to treat of the general system of 



