INTRODUCTION. 25 



rapidity through the confined limits of the Strait of 

 Florida, and pours - a vast volume of tepid water into 

 the cold bosom of the Atlantic. Here, unrestrained, 

 it of course widens its bounds and slackens its speed, 

 though such is its impetus that it may be distinctly 

 perceived even as far as the Great Bank of New- 

 foundland. Nor is its strength then spent; for 

 many curious facts seem to warrant us in con- 

 cluding, that even to the coasts of Scotland and 

 Ireland, and down the shores of Western Europe, 

 this mighty marine river continues to roll its won- 

 derful waters. The temperature of this current is 

 much higher than that of the surrounding water, and 

 this is so uniformly the case that an entrance into 

 it is immediately marked by a sudden rise of the 

 thermometer. Another unfailing token of its pre- 

 sence is the Gulf-weed (Sargassum vulgare), which 

 floats in large fields, or more frequently in long 

 yellow strings in the direction of the wind, upon 

 its surface. The cause of this vast and important 

 current seems to be the daily rotation of the earth. 

 If we turn a glass of water quickly upon its axis, we 

 shall perceive that the glass itself revolves, but that 

 the particles of water remain nearly stationary, owing 

 to the slightness of their cohesion to the glass. To 

 a very minute insect attached to the vessel, it would 

 seem that the water was rushing round in an op- 

 posite direction while the glass remained stationary. 

 Now the earth is whirled round with great rapidity 

 from west to east, and the greatest amount of this 

 rapidity is of course at the equatorial regions, being 



the part most remote from the axis: but the par- 



c 



