2l8 LIGHT SCIENCE FOR LEISURE HOURS. 



of Brazil and Guiana is inclined at a much smaller 

 angle than the south-eastern to the westwardly course 

 of the great equatorial currents. Thus the water which 

 is carried towards the West Indies has time to acquire 

 under the tropical sun a much higher temperature than 

 it had possessed when traversing the Gulf of Guinea. 

 It is divided into two parts by the guasi-barrier which 

 the West Indian Islands (or rather the semi-submerged 

 mountains of which they form the crests) oppose to its 

 progress. A comparatively small portion finds its way 

 into the Caribbean Sea, and making the circuit of the 

 Gulf of Mexico, passes out eastwards round the penin 

 sula of Florida. We may fairly assume that this por 

 tion is comparatively small ; simply because this true 

 gulf stream, passing between Cuba and Florida on an 

 eastern course, would continue so to move for at least 

 some considerable distance, were it not in some way 

 deflected. But it actually turns almost due northwards 

 after passing through the Bahama Sea, traversing the 

 Bernini Narrows on this course, and so onwards towards 

 Hatteras. This would seem to imply that the true Gulf 

 Stream is pressed northwards by the arrival of a much 

 larger body of water which has travelled outside the 

 West Indies. It is true that the diversion of the Gulf 

 Stream northwards may be really caused by the great 

 Bahama Bank. But this would equally establish our 

 position ; for if the Bahama Bank is thus effective in 

 diverting the whole of this now swiftly moving current, 

 the Windward Isles may be assumed to be correspond 

 ingly effective in diverting the greater portion of the 



