1898.] PLANKTON OF THE FAEBOE CHANNEL. 577 



maintains the accurate locking of his net as against Prof. Agassiz's 

 criticism, and makes a very pregnant remark on the point : " Das 

 Netz ist aber nur das Mittel urn beweisende Fange moglichst rein zu 

 erhalten, der wirkliche Bevveis ist die Beschaffenheit des Fanges." 

 The above summary represents briefly the results and conclusions 

 of the chief writers who have studied the question experimentally : 

 in the case of Prof. Agassiz, negative results have led to the 

 assertion of an Azoic zone ; in the case of the * Challenger,' the 

 4 National,' and Prof. Chun, positive observations have led to the 

 conclusion of the existence of a Mesoplankton, but in these cases 

 the mechanism of locking the net has not been sufficiently certain 

 to escape the criticisms of the opponent school. With their 

 results the less extensive experiments of the Prince of Monaco 

 (' 1'H.irondelle '), the ' Pola,' and the ' Gazelle ' are in general accord. 



Results of the Cruises of the ' Research,' 1896 and 1897. 



In commencing to work at this question, I attempted to construct 

 a locking-gear with which not even Prof. Agassiz could find fault ; 

 with the view, firstly, of finally settling the question of the existence 

 of a Mesoplankton, secondly, of endeavouring to ascertain definitely, 

 in a small area and on a small scale, what animals habitually lived 

 in, and what animals descended to, the mid-water strata (matters of 

 very great importance from the standpoint of oceanic distribution). 



I venture to submit that, as long as the Law of Gravity holds 

 good, the absolute closure of my net is indisputable, for it is 

 effected by gravity. It is not only certain in the actions of opening 

 and shutting (gravity being here also the motive power), but, when 

 shut, the net-frame closes so tightly that nothing larger than the 

 net-mesh (1 mm. or -75 mm.) can get into it, either going down 

 or coming up. 



This being so, my observations agree on general lines with those 

 of Chun and the ' National,' and directly contradict the purely nega- 

 tive observations of the ' Blake ' and ' Albatross ' on which Agassiz 

 bases his theory of an Azoic zone. I encountered animals at every 

 depth down to 500 fathoms, the deepest water available. 



The Faeroe Channel was indicated as a suitable district by the 

 thermal conditions ; the depth is small when compared with the 

 great oceans, but the extremely low temperatures met with in the 

 district are those of the greatest depths in open oceans. As regards 

 every thing but pressure, which appears to be an unimportant factor 

 in determining distribution, the conditions of life at 500 fathoms 

 in the " cold area " of the Faeroe Channel seem to be those of the 

 greatest midwater depths known l . 



The Faeroe Channel is certainly a " closed sea " in the technical 



1 The Faeroe Channel was further indicated by the fact that H.M.S. 'Eesearch' 

 was surveying in the Orkney district. I cannot sufficiently express my obliga- 

 tions for the assistance rendered to me on so many sides the recommendation 

 of the Council of the Eoyal Society, the assent of the Lords Commissioners of the 

 Admiralty, the suggestions of Admiral Sir William Wharton and Captain 

 Tizard of* the Hydrographic Office, and the uniformly patient help of Captain 

 Moore and the other Officers of the ' Eesearch ' in both years. 



