'60 WKITINGS OF JOSEPH HENKY, [1855- 



startiug point, to commence the same course anew. If we 

 now suppose the earth, as in the case of the atmosphere, 

 to be put in motion around its axis towards the east, the bot- 

 tom currents, or those flowing towards the equator, coming 

 from a part of the earth moving slower to a part going faster, 

 would fall behind, and thus assume a westerly direction. 

 They would therefore ascend obliquely in a westerly direc- 

 tion towards the surface, flow back towards the pole, (in their 

 course curving constantly towards the east,) and as they 

 cooled would sink down towards the bottom, to return again 

 to the equator. Different portions of the upper surface of 

 the current, as in the case of air, would continue their 

 northerly course obliquely, and descend at intervals, some 

 reaching nearly to the poles. 



The result of the whole of this action would be a series 

 of gyrations to the north and south, with the upper portion 

 turned towards the west, forming a continuous circuit at the 

 equator round the whole earth in a westerly direction, and 

 a circuit in each temperate zone from the west. This would 

 be the result, if the water could be heated to a sufficient 

 depth ; and accordingly it is considered by some that heat- 

 ing the water is the principal cause of the currents of the 

 ocean, — on which account I have so described it. Yet 

 though doubtless a true — I do not consider it a sufficient — 

 cause; but I would ascribe the currents of the ocean mainly 

 to the action of the winds in the belts of the equator and 

 in the two temperate zones. 



The constant westerly winds on either side of the equator 

 would tend to produce a westerly current around the earth, 

 provided no obstructions existed to its free course ; but if, 

 instead of considering the earth as entirely covered with 

 water, we suppose the existence of two continents, extend- 

 ing from north to south, forming barriers across the current 

 we have described, and establishing two separate oceans, 

 similar to the Atlantic and Pacific, then the continuous cur- 

 rent to the west would be deflected right and left, or north 

 £tnd south, at the western shore of each ocean, and would 

 form four immense circuits, namely, two in the Atlantic, 



