-1859] WRITINGS OF JOSEPH HENRY. 61 



one north and the other south of the equator, and two in 

 the Pacific, similar in situation and analogous in direction 

 of motion. For a like reason there will be a tendency to 

 produce a similar whirl in the Indian ocean, the current 

 from the east being deflected down the coast of Africa, and 

 returning again into itself along a southern latitude on the 

 western side of Australia. Besides these great circulating 

 streams, the water supplied by all the rivers emptying into 

 the Arctic basin, as well as that from all the precipitation in 

 this region, returns to the south, and by the motion of the 

 earth must tend westwardly in a current along the eastern 

 shore of each continent between it and the stream flowing 

 to the north. Similar currents, but more difi'use and less in 

 amount, must constantly flow from the Antarctic regions. 



We do not mean to assert that these whirls can be contin- 

 uously traced on the surface of the ocean, though by attent- 

 ively examining the maps their general outline may be 

 marked out. We wish to convey an idea of the general tend- 

 ency of the motions of the aqueous covering of the globe — 

 the central thought, as it were, on which they depend. The 

 regularity of their outline will be disturbed by the configu- 

 ration of the deflecting coasts and the form of the bottom of 

 the sea, as well as by islands, irregular winds, difference of 

 temperature, and above all, by the annual motion of the 

 sun as it changes its declination. The effect of these cur- 

 rents in modifying the climate of different parts of the world 

 has long been recognized, though the detail of the mode in 

 which this is produced has not until recently been pointed 

 out. The Gulf Stream of the North Atlantic carries the 

 warm water of the equator beyond Iceland and the northern 

 extremity of Europe, and it may even be traced to the 

 shores of Nova Zembla. Without its influence the climate 

 of Norway, Great Britain, and the western coast of Europe 

 would be as cold as that of the corresponding parallels of 

 latitude on the North American continent. In like manner, 

 the great circuit of the waters of the Pacific conveys the 

 warmth of the equator along the eastern coast of Asia to 

 Kamtchatka, and gradually cooling in its course, descends 



