fiUI.F STREAM. 223 



the rate of 1000 miles an hour, or 200 miles faster. Now if the 

 water was to be suddenly transferred from the Cape to the equa- 

 tor, this deficiency of motion would cause, (inasmuch as the earth 

 rotates from w6st to east) a very strong current flowing westward 

 at the rate of 200 miles an hour ; or with sufficient power to sub- 

 merge the western continent. No disturbance however occurs, 

 for the water, as it advances into new zones of sea which are mov- 

 ino 1 more rapidly, gradually acquires the different velocity by fric- 

 tion, so that a gentle easterly, or south-easterly current is the re- 

 sult. When the water flows from equatorial to polar regions, a 

 contrary current is produced ; thus the Gulf Stream, issues from 

 the Bahama Channel with a rotary velocity of 940 miles an 

 hour, but when it reaches latitude 40, the water is there moving 

 with a rotary velocity of 766 miles*an hour, or 174 miles an hour 

 slower, hence a westerly or south-westerly current is the result 

 from the excess of rotary motion retained by the stream. 



Having shown some of the causes that produce oceanic cur- 

 rents, we will now consider more in detail the most important. 

 From the best accounts which we have been able to obtain, there 

 seems to be a general set of the waters westward from the west- 

 ern coast of Peru. This current flows nearly westward, but is 

 not much perceived until its entrance into the Indian Ocean, when, 

 strengthened by the northerly currents flowing from the North 

 Pacific, it flows along the east coast of of Africa ; after passing 

 through the Mozambique Channel, between Madagascar and the 

 continent, it unites with another current from the Indian Ocean, 

 and is deflected by the Lagullas banks, which lie off the southern 

 point of Africa, around the Cape of Good Hope. The collective 

 stream is about one hundred and thirty miles in breadth and from 

 7 to 8 warmer than the neighboring water, and runs from the 

 rate of two and a half to more than four miles an hour. The 

 Lagnllus bank rises from an immense depth to within one hun- 

 dred fathoms of the surface, and has perhaps been formed by the 

 joint action of a south-eastern and north-eastern current, which 

 meet here. As the main body of the current does not flow over 

 this bank we may conclude its total depth to be much more than 

 one hundred fathoms. We give here a little chart showing the 



