CURRENTS OF THE SEA. 



141 



operation would overwhelm navigation and desolate the sea ; and, 

 happily for the human race, the great atmospherical machine 

 (§ 90), which actually does perform every day, on the average, all 

 this lifting up, transporting, and letting down of water upon the face 

 of the grand ocean, does not confine itself to an area of two hund- 

 red and fifty-five square miles, but to an area three hundred thou- 

 sand times as great ; yet, nevertheless, the same quantity of water 

 is kept in motion, and the currents, in the aggregate, transport as 

 much water to restore the equilibrium as they would have to do 

 were all the disturbance to take place upon our hypothetical area 

 of one mile deep over the space of two hundred and fifty-five 

 square miles. Now when we come to recollect that evaporation 

 is lifting up, that the winds are transporting, and that the clouds 

 do let down every day actually such a body of water, but that it 

 is done by little and little at a place, and by hair's breadths at a 

 time, not by parallelopipedons one mile thick — that the evapora- 

 tion is most rapid and the rains most copious, not always at the 

 same place, but now here, now there, we shall see actually existing 

 in nature a force sufficient to give rise to just such a system of 

 currents as that which mariners find in the Pacific — currents which 

 appear to rise in mid ocean, run at unequal rates, sometimes east, 

 sometimes west, but which always lose themselves where they 

 rise, viz., in mid ocean. 



271. Under Currents. — Lieutenant J. C.Walsh, in the United 

 States schooner "Taney," and Lieutenant S. P. Lee, in the United 

 States brig " Dolphin," both, while they were carrying on a sys- 

 tem of observations in connection with the Wind and Current 

 Charts, had their attention directed to the subject of submarine 

 currents. 



They made some interesting experiments upon the subject. A 

 block of wood was loaded to sinking, and, by means of a fishing- 

 line or a bit of twine, let down to the depth of one hundred or five 

 hundred fathoms (six hundred or three thousand feet). A small 

 float, just sufiicient to keep the block from sinking farther, was 

 then tied to the line, and the whole let go from the boat. 



To use their own expressions, " It was wonderful, indeed, to 

 see this harrega move off*, against wind, and sea, and surface cur- 

 rent, at the rate of over one knot an hour, as was generally the case, 

 and on one occasion as much as If knots. The men in the boat 



