IN THE DEPTHS 



49 



fathoms would be their limit. The Gulf 

 Stream is supposed to have onward movement 

 at that depth though there is no great accuracy 

 about either the observation or the calculation. 

 Its flow is, of course, more rapid in some places 

 than in others, and its deepest depth would 

 probably be obtained in such passes as the 

 Straits of Florida, where it is forced through 

 a narrow defile; but on the Banks, where it 

 flattens and spreads, it must be much shal- 

 lower. As for the depth of the smaller ocean 

 currents, probably a hundred fathoms would be 

 an approximate estimate. When such a figure 

 is considered in connection with the average 

 depth of the ocean (about two thousand fath- 

 oms), it will be readily seen that no ocean cur- 

 rent more than scratches the surface of the 

 great waters. 



The tides that move about the world used to 

 be considered of superficial penetration also; 

 but it has been matter of surprise more than 

 once to find by casual observation how deep 

 they reach. From steep cliffs looking down 

 through clear water the rush of a four-foot tide 

 can be seen swaying the sea weed a hundred 

 and fifty feet below ; and in the harbors and in- 

 lets the impetus of such a tide is felt to the very 

 bottom. 



Ciirrctili 

 merel;/ 

 scratch the 

 surface. 



The depth 



of the 

 tides. 



