1871.J 



Theory of the Ocean, 



549 



but its result ignored by Dr. Carpenter in favour of the supposed abnormal 

 conditions of temperature and density there. Therefore I fail in being able 

 to agree with Dr. Carpenter's predilection for the density and temperature 

 there, against the "current-drag" indications. If therefore he ignores 

 the " current-drag " test here, he must still more ignore the result at 

 Station 64 by the same means, by boat and basket, and under still more 

 unfavourable circumstances for doing it, when he so sanguinely relies upon 

 it as " a conclusive proof 'that there was at this time a return-current in the 

 mid-channel of this narrowest part of the Strait, from the Mediterranean 

 towards the Atlantic, flowing beneath the constant surface-stream from the 

 Atlantic into the Mediterranean." 



For, with the boat and basket as a means for testing the surface and 

 undercurrent, and without a fixed float attached to the bottom as a 

 stationary point of reference for measuring the rates from, instead of 

 by angles upon a chart of small scale, I cannot, from my experience of 

 such operations (and I do not know any one who has had more expe- 

 rience or given more consideration to the subject for ascertaining the 

 proper or best mode of doing it), agree that the result at Station 64 was 

 a satisfactory or sufficient proof of such an undercurrent outflow as Dr. 

 Carpenter contends for. For with a ship's cutter as a float, and with a 

 force of wind of 4 against the surface-current, and producing so much 

 sea (for Dr. Carpenter states it was necessary in consequence to use a larger 

 boat than before, and not leave it to drift without a crew as on former 

 trials), with these two forces, of wind and short sea together, acting in the 

 presumed undercurrent direction, the result certainly cannot be accepted as 

 a " conclusive proof " of such an undercurrent in 250 fathoms of 0*400, or 

 nearly half a mile per hour. The conclusion to my mind was that the bulky 

 boat, from being exposed most probably nearly broadside on to an easterly 

 wind, and therefore following swell, was drifting faster than the inflowing 

 surface-current from the westward, and thus drew the "current-drag " some 

 little distance to the westward, against the l|-knot surface- current, the 

 "current-drag" being probably in still water in 250 fathoms. I am sure 

 that in this view I shall have many scientific men, landsmen as well as 

 nautical, in full agreement with me, and that for the solution of a question 

 of physical science, and in support of such large views as advocated by 

 Dr. Carpenter, the result was not conclusive. 



One more remark touching the " undercurrent flow up-hill " theory of 

 Dr. Carpenter as the result of the 1028*1 specific gravity and of 55°*3 at 

 the bottom at Station 67, in 188 fathoms. Now both these results are ap- 

 parently to me not abnormal conditions, as compared with the other results 

 in about the same depths, as I have shown in commenting upon the opinions 

 following the density and temperature at Station 65 ; for I can only con- 

 clude from Dr. Carpenter's remarks that the position given of Station 67 

 in 188 fathoms was evidently on the west side of the barrier-ridge, the 

 down-hill or Atlantic side of it, as the line of his section on the Chart of the 



