ANNOTATIONS AND ADDITIONS. 135 



beyond the Equator near the Island of St. Thomas. It gives at the 

 same time a northwesterly direction to a part of the water of the 

 South Atlantic, causing it to strike Cape St. Augustin, and to follow 

 the coast of Guiana to beyond the mouth of the Orinoco, the Boca 

 del Drago, and the coast of Paria. (Rennell, Investigation of the 

 Currents of the Atlantic Ocean, 1832, pp. 96 and 136.) The New 

 Continent, from the Isthmus of Panama to the northern part of 

 Mexico, opposes a barrier to the farther continuance of this move- 

 ment of the waters, and thus the current is constrained to assume a 

 northerly course off Veragua, and thence to follow the windings of 

 the coast of Costa Rica, Mosquito, Cainpeachy, and Tobasco. The 

 waters which enter the Mexican Gulf between Cape Catoche of 

 Yucatan and Cape San Antonio of Cuba, after completing a great 

 rotatory movement or circuit, by Vera Cruz, Tamiagua, the mouth 

 of the Rio Bravo del Norte, and that of the Mississippi, force their 

 way northwards through the Bahama Channel, and .re-issue into the 

 open ocean. Here they form the well-known " Gulf Stream," a 

 current or river of warm and rapidly moving water, flowing in an 

 oblique or diagonal direction, carrying it farther and farther from 

 the North American coast. Ships from Europe bound for this 

 coast, when uncertain in respect to their longitude, are enabled by 

 this oblique direction of the current to direct their course, as soon 

 as they reach the Gulf Stream, by observations of latitude only. 

 The position of this great current was first indicated with accuracy 

 by Franklin, Williams, and Pownall. 



From the 41st degree of latitude, the river of warm water, which 

 has been gradually diminishing in rapidity and increasing in breadth, 

 turns suddenly to the east. It almost touches the southern edge of 

 the great Newfoundland bank, where I found the greatest amount 

 of difference between the temperature of the warm water of the Gulf 

 Stream, and that of the waters resting on the banks and subjected 

 thereby to a cooling process. Before the stream reaches the western- 

 most of the Azores it divides into two branches, one of which, at 

 least at certain seasons, advances towards Ireland and Norway, and 

 the other towards the Canaries and the West Coast of Africa. This 

 Atlantic rotatory movement (described by me more in detail in the 

 first volume of my Voyage to the Equinoctial Regions), explains the 



