OCEANOGRAPHICAL INVESTIGATIONS 



7 



taking a great majiy dredgings at different depths, and came to 

 the conclusion that marine animals were distributed in zones of 

 depth, each characterised by a special assemblage of species. 

 He divided the area occupied by marine animals into eight 

 zones, in which animal life gradually diminished with increase 

 of depth, until a zero was reached at about 300 fathoms. He 

 supposed that plants, like animals, disappeared at a certain 

 depth, the zero of vegetable life being at a less depth than that 

 of animal life. In his Report on the Investigation of British 



Marine Zoology by means 

 of the Dredge (1850), Forbes 

 suggested that dredgings off 

 the Hebrides and the Shet- 

 lands, and between the 

 Shetland and Faroe Islands, 

 would throw much light on 

 marine zoology, thus point- 

 ing to the scene of the 

 subsequent important work 

 carried on by Carpenter 

 and Wyville Thomson, and 

 Murray and Tizard. 



In 1844 Loven carried 

 on researches on the distri- 

 bution of marine organisms 

 along the Scandinavian 

 coasts, confirming and ex- 

 tendine the observations 

 recorded by Forbes, and m 

 1845 Johannes Mliller com- 

 menced to study the pelagic 

 life of the sea by examining 

 samples of sea-water and by 

 means of the tow-net, thus giving a great impetus to the study 

 of marine biology. 



In 1845 Sir John Franklin set sail on his ill-fated North 

 Polar Expedition, accompanied by Harry Goodsir, who recorded 

 the results of dredging in depths of 300 fathoms. 



In 1846 Spratt took dredgings in the Mediterranean down 

 to a depth of 310 fathoms; he afterwards brought up shell- 

 fragments from a depth of 1620 fathoms in the Mediterranean. 

 In 1850 Michael Sars published the results of his dredgings 

 off the coast of Norway, giving a list of 19 species living at 



Forbes' 

 observations 

 in ^^igean Sea. 

 Marine 

 animals 

 distributed 

 in zones of 

 depth. 



Zero of life 

 in the sea. 



Professor Michael Sars. 



John Franklin 

 and Goodsir. 



Spratt. 



Michael Sars 

 and G. O. 

 Sars. 



