68 



On Some Experiments with " Drift Bottles." 

 By James Johnstone. 



Two series of experiments have already been made 

 from our Laboratory, with the object of determining the 

 direction taken by small objects floating at the sm-face, 

 in various parts of the Irish Sea. The results of these 

 have been published in former reports.* In both series the 

 portion of the Channel N. of Holyhead was mainly dealt 

 wdth, and the general result was to indicate an apparent 

 drift to the N. and N.E. on the E. side of the middle of the 

 Channel, and a N. to W. drift towards Ireland on the W. 

 side. The importance of the experiments was the probable 

 indication of the general drift of fish eggs from the 

 spawning grounds. It had been suspected, however, from 

 some observations made by the late E. L. Ascroft and 

 others on floating wreckage, that fish eggs spaw-ned in the 

 southern parts of the District might find their 'w&j into 

 the shallow waters oft' the Lancashire and Cheshire coasts, 

 and it became desirable to make some experiments to test 

 this supposition. Accordingly, Prof. Herdman, while going 

 out to Ceylon at the beginning of the year, set free some 

 200 bottles from the s.s. " Derbyshire," ou his way down 

 the Channel on board that vessel. The bottles were of the 

 same size, aud contained stamped and addressed postcards 

 of the same description, as those used in the two former 

 experiments. The experiment was very successful, and 

 118 of the bottles were subsequently picked up, and the 

 postcards forwarded to the laboratory. 



The bottles were set adrift in lots of ten, and the data 

 obtained are given in the following Table : — 



* Lancashire Sea-Fisheries Laboratory Reports for 1895 and 1898. 



