4 Fishery Board for Scotland. 



especially near the central areas, of the shape of the cyclonic system 

 which was revealed by our former investigations. The experiment 

 was of fm-ther value as it contributed independent confu-mation of 

 the general trend of the deep ciu'rents previously determined. 



From October 1913 up to the present date, January 1916, only 

 27 more bottles of this series have been returned to us, 14 having 

 been trawled up from the bottom, and 13 picked up on the beach. 



It will be remembered that the bottles of this series were put 

 away in lots of five at a time, so I have distinguished the cards of 

 each lot by means of a reference number and the letters a, b, c, d, and e. 



Of the 14 bottles trawled up, 9 of them (3c— 5a— 12c— 14a— 62e— 

 63c — 109a — ir2a — ^115b) have followed a direction which agrees with 

 the curves as shown on the charts of the previous Reports, and 5 of them 

 (40a — 56c — 61a — -62c — 125i) seem to have drifted for a short distance 

 in a contrary direction. But all of them have been so long adrift, 

 two to five years, and have covered, with one exception, such com- 

 paratively short distances, 5 to 320 miles, that the mean velocity 

 attained by the 14 bottles, always assuming, as hitherto, that they 

 have followed a straight line between their initial and terminal posi- 

 tions, works out at slightly less than 12 miles per year, a speed which 

 does not sensibly modify our former results. 



The exception to this slow progression was bottle 12c, which was 

 put away to the westward of the Orkney Islands, and was picked up 

 four years afterwards, 60 miles N.E. from Spurn Point, having ap- 

 parently drifted round the north of the Orkneys, and down the east 

 coast of Scotland for a distance of 322 miles, at an average speed of 

 25 miles per 100 days. 



This is considerably above the average speed on this route, so much 

 so that one might infer that the bottle had drifted on the surface, yet 

 it was trawled up in 21 fathoms of water. 



The remaining 13 bottles of this series were picked up on the 

 beach, eleven of them on the Norwegian coast, all of which appear 

 to have traversed much the same track as was apparently followed 

 by others that have been carried to foreign coasts ; and two were 

 found on the Shetland Islands. 



One of these Shetland drifts, 40c, is of considerable value, as it 

 appears to me to indicate that the system of deep currents forms a 

 closed curve. This bottle was carried from the south edge of the 

 Witch Ground to Sandwick Bay which is close to Sumburgh Head. This 

 distance in a straight line measures 120 miles, but the direction of drift 

 is diametrically opposite to that which has been firmly established. 

 But it is easy to reconcile this apparently retrogressive movement 

 with the curves on Chart III. of last Report. A reference to the 

 chart attached hereto shows that the centre of the cyclonic system 

 lies approximately over the Witch Ground, and it is highly probable 

 that the bottle may at first have been carried a little to the eastward, 

 then up the east side of the Witch Ground in a northerly direction, 

 and finally to the westward into Sandwick Bay. Two hundred and 

 fifty miles would be a generous distance to allow for this circular 

 route, and as the bottle was 4 years 3 months on the journey, its 

 average speed would be about 16 miles per 100 days, which compares 

 favoirrably with the speeds already determined. 



In support of this conjectm'e it might be as well to examine for 



