OF THE SEA AND LAND. 45 



of those countries ; when proceeding down the coast 

 of Spain to Africa, it completes that round which main- 

 tains a perpetual circulation of the waters throughout 

 a large portion of the globe. If these currents have not 

 yet been thoroughly investigated in other parts of the 

 ocean, there is abundant evidence of their existence every 

 where, with sufficient proof of their power in distri- 

 buting the submarine alluvia, in the facts already men- 

 tioned respecting the shores of Mexico. But this power 

 in the ocean is visible, in comparing those rivers which 

 produce neither islands nor deltas, with those in which 

 these occur. The Congo, the Plata, the Oroonoko, the 

 Maranon, and many others, enter the ocean, deep and 

 bold, unattended by those obstructions which charac- 

 terize the Nile, the Euphrates, the Wolga, and the Da- 

 nube; yet they do not convey less earth in proportion, 

 as is evident in the lateral plains which they have pro- 

 duced : while this difference of result must be sought in 

 the ocean currents which the former meet at their junc- 

 tions with the sea : thus indicating the mode in which 

 the materials, which would ptherwise accumulate to 

 " shallow their sestuaries, are disposed of. The slightest 

 geographical knowledge will show these differences be- 

 tween the Congo and the Plata, contrasted with the Nile 

 and the Danube : and these obvious considerations, 

 which any one can localize, will explain the various cir- 

 cumstances attending our several European rivets, and 

 the positions of their subaqueous alluvia. That wt : ch 

 cannot be at rest in their own sestuaries, must collect in 

 the lee parts of the broader channels, or at the points 

 of repose between tide streams. 



Alittle reflection on the laws which regulate the move- 

 ments of water in narrow channels and determine the 

 equilibrium in different places, will now show that the 

 form of the bottom cannot thus be changed, without pro- 



