68 



the tropics, which receive the cold waters of the 

 northern regions, the whole mass of water is agi- 

 tated to a very great depth. We are ignorant 

 if it be the same, when the movement of pro- 

 gression, which must not be confounded with 

 the oscillation of the waves, is the effect of an 

 external impulse. Mr. de Fleurieu, in his nar- 

 rative of the voyage of the Isis # , cites several 

 facts which render it probable that the sea is much 

 less still at the bottom than naturalists gene- 

 rally admit. Without entering here into a dis- 

 cussion which we shall treat hereafter, we shall 

 only observe, that if the external impulse is con- 

 stant in it's action, like that of the trade winds, 

 the friction of the particles of water on each 

 other must necessarily propagate the motion of 

 the surface of the ocean even to the inferior 

 strata ; and in fact this propagation in the Gulf- 

 stream has long been admitted by navigators, 

 who think they discover the effects in the great 

 depth of the sea wherever it is traversed by the 

 current of Florida, even amidst the sand-banks 

 which surround the northern coasts of the Unit- 

 ed States. This immense river of hot waters, 

 after a course of fifty days, from the 24th to the 

 45th degree of latitude, or 450 leagues, does not 

 lose, amidst the rigors of winter in the tempe- 

 rate zone, more than 3 or 4 degrees of the tem- 



* Voyage made by order of the king, in 1768 and 1769, 

 to try the marine time-pieces. Vol. i, p. 5] 3. 



