a ; THE GULF STREAM. 203 
tom, say to 2,000 fathoms, were the winds to blow without intermission 
in one direction during that time, with the average power they are 
known to possess.* 
We may imagine the whole of the mass of the Atlantic within the 
belt of the trade winds to be moving in a westerly direction and im- 
pinging upon the continental slope of South America,t and upon 
the Windward Islands, at which point it is deflected either in a south- 
erly or northerly direction or forces its way into the Caribbean. In 
our present state of knowledge it is difficult to trace the path of the 
equatorial water as it is forced into the eastern Caribbean. Com- 
mander Bartlett supposes that it is warmed in the Caribbean by cireu- 
lating round the whole basin. The water which is swept into the 
Caribbean by the trade winds through the passages between the Wind- 
ward Islands and, being then driven into the Old Bahama Channel 
funnel, flows through the Windward Passage, represents a far greater 
mass than that which can find its way into the Gulf of Mexico through 
the Straits of Yucatan or that of the stream flowing north through the 
Straits of Bemini. This is the actual Gulf Stream, a body of super- 
heated water filling the whole straits; it has an average depth of about 
300 fathoms and a velocity extending to the bottom of at least 34 miles 
an hour. 
The section of the Yucatan Channel is too small to allow for an out- 
flow equal to the inflow into the Caribbean,§ so that, after the trades 
have ceased to force the equatorial water into the Caribbean basins, it - 
must remain there a considerable length of time before it passes into 
the Gulf of Mexico, where, owing to similar differences between the 
rate of inflow and outflow, the water must still become more super- 
heated. 
We must therefore consider the Gulf Stream proper, as it emerges 
from the Straits of Bemini, as an immense body of super-heated water 
“It is therefore possible that currents which owe their existence to causes that 
have been modified to a certain extent should still exist in the ocean long after the 
conditions producing them (acting from the surface) have ceased to be effective by 
any break of continuity due to the interposition of islands or of banks in the track 
of oceanic currents. 
i Did the Gulf Stream not meet continental masses, it would simply expand north 
and south, losing its initial velocity, and gradually cool down towards the poles, 
the cold penetrating all the deeper portions of the ocean, just as we find it reaching 
the higher summits that rise above the line of perpetual snow. 
{Current observations taken by Mitchell off the coast of Cuba, in the deep part 
of the Gulf Stream, show that it has a nearly uniform and constant velocity for a 
depth of 600 fathoms, although the temperature varies 40° F. 
§ A part of this water emerges again at a higher temperature between Guade- 
loupe and Haiti and joins that portion of the equatorial current which finds its way 
into the Windward Passage. This increased temperature may he due to its pass- 
ing over shoals and banks at the northeastern end of the eastern basin of the 
Caribbean. 
