Oct. 24, 1872] 



NATURE 



521 



of the /Egean above that of the Euxine ; whilst, I argued, 

 if the salt continually passing out of the Black Sea by 

 the surface-current were not thus replaced, the con- 

 tinual excessive influx of River water would, in time, 

 wash the whole of the salt out of its basin. 



My position was assailed by Captain Spratt, who affir- 

 med (i) that his own experiments in the Dardanelles had 

 shown the existence of still water beneath twenty 

 fathoms ; and (2) that the return of salt to the Black Sea 

 was effected by a surface in-current during the winter, 

 when the ri\-ers are low, and when the wind setsy>i;v« the 

 ^Egean along the Dardanelles, the Sea of Marmora, and 

 the Bosphorus. 



On an examination of Captain Spratt's experiments, 

 however, I came to the conclusion that, when rightly in- 

 terpreted, their results bore out my view of the case ; 

 and, as I stated in my letters of Nov. 14, 1S71, my inter- 

 pretation of them had the sanction of three eminent 

 Naval Surveyors. Captain Spratt maintained that be- 

 cause a surface-buoy from which a " current-drag " was 

 suspended at a depth beneath twenty fathoms remains 

 stationary, the waters in which the " drag " hangs must 

 also be motionless. To me, on the other hand, it ap- 

 peared indisputable that if the surface-buoy is floating in a 

 current which puts a strong strain on the suspending 

 line, that strain would draw the " current-drag " through 

 still water ; so that the stationary condition of its sus- 

 pending buoy can only be accounted for on the suppo- 

 sition that the action of the surface- current on it is 

 neutralised by some pressure in the opposite direction, 

 which can bo nothing else than that of an under-current 

 nieetint; the " current-drag." 



The question is discussed in an Appendix to the forth- 

 coming Report of my last year's work in the -Shear- 

 liiater, of which the following (written on board of her 

 a year ago) is an extract : — 



" Now since, according to Captain Spratt, this station- 

 ary condition of the 'current-drag' was shown at all 

 depths below forty fathoms in the Sea of Marmora (even 

 down to 400 fathoms), and at all depths below twenty 

 fathoms in the Dardanelles, it seems an irresistible 

 conclusion that whilst there is a rapid superficial out- 

 current, running in the Dardanelles at the rate of 2] 

 miles per hour, there is a deeper under-cwxreni from 

 twenty fathoms to the bottom, running more slowly iu- 

 wards from the .Egean into the Sea of Marmora through 

 the Dardanelles, and thence, it may be presumed, through 

 the Bosphorus, into the Black Sea. And this conclusion 

 finds complete confirmation in the results of a comparison 

 between the respective Densities and rates of movement 

 of the Dardanelles water at different depths, as observed 

 by Captain Spratt himself. For whilst the progressive 

 decrease in the movement of the ' current-buoy,' from 

 2\ knots at the surface to almost nothing at twenty 

 fathoms, indicates (as just now shown) first a cessation 

 of all movement in the stratum in which the ' current- 

 drag ' hangs, and then a reversal in the direction of the 

 current as the lower depth is approached, — the Density 

 increased from 1,020 at the surface to 1,028 at twenty 

 fathoms, and 1,029 '^' forty fathoms ; the surface-water 

 thus corresponding with that of the Sea of Marmora, whilst 

 thewater of the entire stratum from twenty fathoms to the 

 bottom was equal in density to that of the Mediter- 

 ranean. 1 hold, then, that the existence of an Under- 

 current of dense Mediterranean water through the Dar- 

 danelles into the Sea of Marmora, is incontestably proved 

 by the very experiments and observations which have 

 been adduced by Captain Spratt as demonstrating the 

 unsoundness of the Under-current doctrine." 

 is Having understood that the SJieariuater, on the com- 

 pletion of the Survey of the Gulf of Suez, would proceed 

 to the Dardanelles, I requested the Hydrographer to 

 direct that the question of the Under-current should be 

 thoroughly examined ; and he issued instructions ac- 

 cordingly. 



I yesterday learned through the Levant Herald : - 

 (i) that the existence of a strong Under-current has been 

 placed beyond all question, a boat having been carried 

 along by the-" current- drag " suspended from it, in opposi- 

 tion to the surface-current : (2) that the rate of this Under- 

 current is estimated as greater than the speed of the 

 Shearwater's steam-launch ; and (3) that it ntns at a 

 depth of twenty fathoms,— precisely that at which my in- 

 terpretation of Captain Spratt's experiments has led me 

 to predicate its existence. 



I venture to think that this verification of my predic- 

 tion will be regarded as a confirmation of the general 

 Physical Theory of Under-currents on which it was 

 based ; and it is now for those who oppose that Theory 

 to show by what other force than the difference in the 

 ■weight of the .'Egean and the Black Sea columns, con- 

 sequent upon their great dilference in Specific Gravity, 

 the Dardanelles Under-current can be sustained. 



William B. Carpenter 



NOTES 



Mr. C. Meldru.m writes from Mauritius that he has be?n 

 looking into the subject of the West Indian hurricanes, and l-.e 

 believes that they show a periodicity of frequency correspondiiii; 

 nearly with that of sun-spots. So far as he has yet examined 

 the subject, the maximum of cyclone frequency is a year or t«o 

 after that of sun-spots. It was so ten years ago, and is so agaji 

 probably, the mean cyclone frequency occurring in 1862, a- J 

 this year, 1S72, being the most marked for hurricanes since. 

 We greatly regret to hear that Mr. Meldrum is suffering severely 

 from illness brought on by over-work. It will scarcely he 

 credited that the only allowance made to him Ijy the Goverji- 

 ment for an assistant is 50/. per aimum ! 



We learn from the Gardener's Chronicle that M. Mihi - 

 Edwards has undertaken a task for which all naturalists o«v 

 him thanks. The archives of the Museum of Natural History 

 in the Jardin des Plantes contain a"_collection of 6,000 volumts 

 and more than i , 500 manuscripts, which are almost entirely ui - 

 known to the scientific world ; for nearly 60 years the dust that 

 lay upon them has never been disturbed. In 1803 it was pro- 

 posed to create a special department for these and other worf s 

 and documents, but the idea was abandoned, and since that time 

 the collection has remained huddled away in a corner, on accouit 

 of space being wanting in the library of the museum. M. Milne 

 Edwards has determined that such a state of things shall not be 

 perpetuated, and has arranged that the collection shall be cart- 

 fully examined, catalogued, and placed at the disposition of the 

 scientific world. The manuscripts include a considerable 

 number by Buffon, Cuvier, and Daubenton ; there is a series of 

 24 pen-and-ink drawings by the last-named naturalist, represen!- 

 ing the various types of Merino sheep, and exhibiting great 

 artistic ability, and many albums filled with drawings of plant-; 

 and flowers. It is proposed to add the books to the library (T 

 the museum, but there is so little space to be disposed of then', 

 that it is expected the MSS. will be transferred to the gre.it 

 National Library, in the Rue Richelieu. 



Sir David Baxter, who endowed in his life-lime a Chair of 

 Engineering at the University of Edinburgh, has by his will JlIc 

 the munificent gift of 40,000/. for the general purposes of tlic 

 University. 



The death is announced, on the l6th iust. at Torquay, at t! e 

 age of 75, of Lady Hooker, widow of Sir W. J. Hooker, K. I'., 

 formerly Director of the Royal Gardens, Kew. 



Mr. Ray Lankester, M.A., Fellow of Exeter College, O. - 

 ford, writes to correct the statement in our University Intelligence 

 last week, that he h.as been apiminted Deputy to the Linacre 



