10 



OK THE CAUSES OF THE 



Storm raged in the Bay of Bengal near the mouth of the 

 Hoogly, when the tide, at the mouth of that river, rose more 

 than twelve feet above the ordinary height of the springs !" 

 These are a few of the numberless instances which might be 

 adduced to shew that wind, acting on the surface of confined 

 water, produces upon it great effect in raising its level ; but 

 when there is ample space for the water to move forward, the 

 wind readily produces a current, and it is evident from the 

 nature of the force that is in action, that that current will, 

 in deep water, extend to depths proportioned to the length of 

 time that the wind has acted on the water which is in motion. 

 There are parts, other than those which have been men- 

 tioned, where winds evidently create oceanic currents. One 

 blows from the south along the western coast of South 

 America, and an oceanic current is found moving with it, 

 increasing in velocity with the increase of the wind and carry- 

 ing comparatively cold water even to the equator. This 

 current of the ocean runs from south to north, and not from 

 east to west, as the so-called rotatory currents do ; the surface 

 of the land therefore moving easterly, faster than the water 

 resting on it, cannot account for this current, which must be 

 produced by the wind. There is another extensive current 

 which is thus described : — " In the Indian Ocean we find 

 the well known current that runs from south to north, 

 from the west coast of New Holland, (Australia,) and 

 from the Island of Sumatra, as far as the bottom of the 

 Gulf of Bengal." It also " impels one of its branches through 

 the Strait of India; thence it runs with great violence into the 

 Chinese Seas, and was found by La Perouse to be of great 

 strength in the Sea of Japan, and in the Channel of Tartary." 

 (p. 35, Lizars.) This great current, it appears, has to cross the 

 equator near Sumatra, from which part there is open sea ex- 

 tending say three thousand miles to the coast of Africa, and if 

 the water of the ocean were here left behind by the land, it 

 would have an apparent current westward, that is in the diree- 



