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GREAT CUBRENT8 OP THE OCEAN. 



extent of sea, and blows into this gulf towards the shore ; yet 

 this wind, short as is its course, evidently forces the water 

 forward and creates the oceanic current, no other cause being 

 found to produce it in this case. But if wind, by blowing 

 over so comparatively small an extent of sea, can produce 

 such a rapid oceanic current as that which exists in the Gulf 

 of Guinea, there can be no reason given that the same agent 

 should not, by passing over the Pacific, the Indian, and the 

 Atlantic Oceans, produce strong currents in them. 



It has been long observed that wind blowing over water 

 towards land, acts on water which is obstructed by the land, 

 with a force sufficient to raise it to a considerably higher level 

 than it would otherwise attain. This has been particularly 

 noticed in the river Thames, where a strong wind acting in 

 the same direction as the flowing tide, raises the water much 

 above the proper tidal elevation, whilst the wind acting in the 

 opposite direction to the tide produces a contrary result : the 

 same effects are experienced in the Severn. In the canal 

 between Runcorn and Manchester which has a level of con- 

 siderable extent, the wind, when it blows strongly from 

 Runcorn, raises the water above the true level at Manchester. 

 The same kind of effect is produced in the Forth and Clyde 

 Canal. When the wind has for some time blown strongly from 

 Suez, at the head of the Red Sea, it is said that the water of 

 that sea has been forced southward to so great an extent, as 

 to leave the bed of the sea almost fordable, though, at other 

 times it is deep. Mr. Taylor, the astronomer at Madras, 

 informs us that " the north-east monsoon sets in at that place 

 about the 19th of October, and along with the wind a current 

 sets along the shore. It reaches its maximum velocity about 

 the 1st of November, running then three miles an hour. 

 During this interval the sea, on a squally day, rises two and 

 a half feet above and sinks two and a half feet below its mean 

 level, and, in the case of a gale of wind, it may possibly reach 

 to double this amount." " On the 21st May 1833, a terrible 



