INTRODUCTION. 13 



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 warrant us in concluding, that even to 

 the coasts of Scotland and Ireland, and down the 

 shores of "Western Em-ope, this mighty marine river 

 continues to roll its wonderful waters. The tempera- 

 ture of this cmTcnt 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 presence is the Gulf-weed {Sargassum 

 vulgare), which floats in large fields, or more fre- 

 quently 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 station- 

 ary, 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 

 opposite 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 particles 

 of water, for the same reason as those in the glass, to 



