394 



HYDROGRAPHY. 



flow is not hindered ; it is free from all barriers, and passes onward in 

 a steady and sometimes strong gale towards the heated area, varying 

 in duration, interchanging its particles, and ever acting under the 

 simple but efficient law impressed upon it. 



But to return to the circulation. Let us take an atom of the South- 

 east Monsoon of the Pacific, found in the southern hemisphere, south- 

 ward of the Tropic of Capricorn, near the 180th degree of longitude, 

 during the winter season (from May to October). It will flow to the 

 northwest, west-northwest, or west, passing through Torres Straits, 

 over part of New Holland on the south, or New Guinea on the north; 

 thence over the Banda and Java Seas into the Indian Ocean, where it 

 will pass to the Equator at the calm area; it has then become heated, 

 is specifically lighter, and rises to the upper strata, where its tempera- 

 ture is lost ; thence it is induced to the northeast towards the heated 

 areas of Hindostan, China, or Arabia, in the Southwest Monsoon, and 

 onward to the Himalaya Mountains, which intercept its course. 

 Being unable to pass this high barrier, it must flow towards the east 

 or the west ; as it is induced, most probably in the latter direction, to- 

 wards the heated deserts of Iran, Syria, or the great Sahara of Africa, 

 it unites with the great current which passes over it, and flows onward 

 to the west, to join the Northeast Trade Wind. But if this atom 

 should have been induced, in the first part of its route, toward the 

 central heated area of New Holland, to restore the equilibrium, it 

 would then have flowed into the Southeast Trade Wind of the Indian 

 Ocean, thence across the South of Africa have joined the Southeast 

 Trade Wind of the South Atlantic, and with it passed to the Equatorial 

 calms north of the Equator ; thence westward over the continent of 

 America, to join the flow over the ocean whence it set out, — having 

 performed more than an entire revolution ; and at the average rate of 

 six miles per hour, it would have required just the half year to have 

 completed this circulation. In the same way it may be shown that 

 other atoms pass in various directions from the Variables, through the 

 Monsoons, make the circuit without interfering with each other, flow- 

 ing in the utmost order and harmony. These routes may be readily 

 seen by an inspection of the map, and traced from the Polar Circle into 

 the Variables, and through the Monsoons, to the Equatorial currents, — 

 and by noticing the mark on the arrow, it may be seen whether their 

 flow is in the summer or winter season of the hemisphere. Thus the 

 connection is formed and kept up between the Polar and Equatorial 



