160 PHYSICAL INVESTIGATIOi^S. 



down in sucli a way as to lead to the supposition that a good deal 

 of failure may often arise from tlie nets not going deep enough. 

 The fish prefer^ apparently, so far as the inquiry has gone, the lower 

 to the higher temperature.'^'^ 



Again, in summarising the results of physical investigations 

 carried out for the Fishery Board for Scotland, Dr. John Gibson 

 says, " I am not sure that the observations already made do not 

 even now point to a connection between the presence of Atlantic 

 water in the Moray Firth as a condition of successful inshore 

 herring fishing. In the summer of 1883, when surface Atlantic 

 water filled the Moray Firth, the inshore herring fishings in this 

 firth are reported to have been unusually productive ; while, on the 

 other hand, in the summer of 1886, when water from the bottom of 

 the North Sea filled the firth, during the month of August at any 

 rate, it is reported that more than one half of the entire season's 

 catch in the inshore waters was made during one single week, and 

 that all the rest of the season these inshore waters were compara- 

 tively unproductive, "t 



That this opinion is general is shown by the extensive physical 

 investigations carried on by the German Government, both by 

 means of coast stations and exploring expeditions, such as those of 

 the '' Pommerania "} and the ''Drache,"§ by the Norwegian 

 Government, and by the U.S. Commission of Fish and Fisheries, the 

 last named being about to publish an extensive series of observations 

 of temperature and density on the Atlantic seaboard. 



So far, however, the problem has only been stated ; it has been 

 shown that a more or less indirect relation exists between the 

 physical and meteorological conditions affecting any particular 

 region of the sea, and the quantity and quality of the fish to be 

 caught in that region. Further, it has been shown that two methods 

 of investigation give the most promising results : — (1) Continuous 

 observations of temperature at fixed stations extending over a con- 

 siderable period of time ; and (2) Expeditions making a rapid 

 survey of a certain area at intervals ; the distribution of temperature 

 being observed, and samples of water collected for subsequent exa- 

 mination. 



These facts ascertained and defined, it remains at present to 

 increase as far as possible, in either or both of the above-mentioned 

 directions, the material for discussion. 



In organising, at the request of the Director, a section for physical 



* Journ. Scott. Met. Soc, 1876, vol. v, p. 30. 



t Report of the Fishery Board for Scotland, 1888, p. 471. 



X Jaliresbericht der Commission zu Wissenschaftlichen Uutersuchung der deutschen 

 Meere in Kiel, 1872-3, Berlin, 1875. 



§ Ergebnisse der Untersuchungsfahrten der Drache, Berlin, 1886. 



