I 



36 NATURAL SCIENCE. Jan., 



an exceptionally good opportunity of observing the circulation ; but 

 the observations of the "Drache" and other vessels in former 

 years indicate a similar arrangement. 



It is certaniy remarkable that there should be so much evidence 

 that oceanic water reaches the east coast of Scotland, as a bottom 

 current, just at the time the herring-fishing usually begins, and pene- 

 trates southwards at a rate which appears to agree closely with the 

 progressively later date of the fishing as we go southward. It has 

 already been stated that, in the course of the work of the Committee of 

 the Scottish Meteorological Society, Dr. Buchan found that the herring 

 appeared off the east coast of Scotland about the time the surface 

 temperature of the sea reached 55^° F. This would usually occur 

 about the middle of August, the time at which we should expect the 

 oceanic water to reach the fishing grounds. The further conclusion 

 that large catches of herring were most frequently made in cold 

 patches of water becomes extremely interesting from the fact that, 

 as was shown by the present writer from a discussion of extensive 

 materials in the hands of the Scottish Meteorological Society (Jouvn. 

 Scott. Met. Soc, vol. viii., p. 332), the great fishing grounds occur 

 where the prevailing winds are off the shore, and that the cold patches 

 are therefore patches of water welling up from the bottom. If our 

 view of the circulation be correct, the bottom water is, for the time 

 being, oceanic water. 



Whether the fresh supply of oceanic water reaching our coasts 

 really does contain a markedly greater amount of oxygen than the 

 water whose place it takes, can only be ascertained by analysis of 

 actual samples ; and the further question, whether the herring comes 

 with the oceanic water or to it must be dealt with by zoologists. 

 These investigations could be carried on concurrently with inquiries 

 into the circulation of the waters, depending on the ordinary physical 

 methods. In the light of the results obtained by the Swedish oceano- 

 graphers, it can scarcely be disputed that the work of the " Jackal " 

 places the scientific investigation of the whole subject in a position 

 of the highest importance to our fisheries. To carry out the work 

 satisfactorily two ships would be necessary, both fully equipped with 

 the apparatus devised by Professor Pettersson for use in shallow 

 waters. One steamer should be of at least 1,200 or 1,500 tons, able 

 to carry on work in the Faeroe-Shetland Channel, even in moderately 

 rough weather ; and she should be provided with apparatus for 

 sounding in deep water, and with a launch to enable tow-netting 

 and similar work to go on during the deeper soundings. A 

 smaller vessel, capable of steaming at a fairly high rate of speed, 

 and specially handy in turning and manoeuvring with sounding 

 lines and nets, could be devoted to the in-shore waters, keeping 

 a special look-out in the neighbourhood of the fishing grounds. 

 Both vessels should remain constantly at sea during the fishing 

 season, so that no change might pass unnoticed; and favourable 



