^0 LEVELS OF THE ATLANTIC AND PACIFIC 



being raised, and the latter depressed by the 

 action of that force; so also, in accordance with 

 that theory, iriust the action of westward pressure 

 tend to raise the level of the waters of the Caribbean 

 Sea and Gulf of Mexico above the level of the ad- 

 jacent parts of the Pacific Ocean. For the full force 

 of westward pressure in the North Atlantic is tend- 

 ing to heap up the waters of the Atlantic against 

 the eastern side of the Isthmus of Panama : whereas 

 the westward pressure of the Pacific tends to carry 

 away the water, and depress the level of the Ocean 

 on the western side of the Isthmus of Panama. 



Now, that the waters of the Caribbean Sea and 

 Gulf of Mexico are actually raised above the level 

 of the central parts of the Atlantic, is a very 

 general opinion. This difference in level being attri- 

 buted to the action of the trade -winds; and, accord- 

 ing to our theory, being the result of the westward 

 pressure of the ocean itself, the trade -winds contri- 

 buting towards it, but being comparatively a very 

 trivial cause. 



If the relative level of the waters of the Pacific and 

 Atlantic Oceans adjacent to the Isthmus of Panama 

 be determined by the action of evaporation, it appears 

 reasonable to expect that, all other circumstances 

 being similar, the Atlantic waters should be the 

 lower, because not only is the heat of the Caribbean 

 Sea and Gulf of Mexico greater than that of the 

 adjacent parts of the Pacific; but also, from those seas 



