52 THE OCEANOGRAPHY OF THE NORTH-WESTERN OCEAN [PART I 



which just allow us to see, in a most imperfect way, the working of 

 some complex natural law. The door is opened, so to speak, and 

 then closed in our faces. That the cause of this " secular 

 periodicity " is a cosmic one we can scarcely doubt ; but what 

 is it ? 



Climate and hydrography. We will consider later on in 

 what manner the hydrographical conditions of the sea influence 

 the abundance and migrations of fishes and other marine organ- 

 isms, but in the meantime some notice may be taken of the 

 connection between hydrographical and climatic phenomena. 

 Every year the European Stream brings into northern seas an 

 immense mass of water, the temperature of which is greater than 

 that of the water which is normally present in those areas. An 

 incredibly great amount of heat is thus annually yielded up 

 to the atmosphere in these latitudes. The moist and temperate 

 climate of the British Islands is the result of the oceanic circula- 

 tion we have been considering. If the North Atlantic were a 

 streamless ocean the isothermal lines would be roughly parallel to 

 those of latitude ; the sea round the British Islands would have a 

 mean temperature equal to that of the sea off the coast of Labrador ; 

 and the climate of the land would be changed in a similar manner. 

 But the isothermal lines are not parallel to those of latitude, but 

 are bent up strongly to the north-east ; the mean temperature of 

 the sea off the coast of Labrador varies from 2^ C. to 5° C, while 

 that of the sea off the coasts of Great Britain is 10° C. to 13 °C. ; and 

 the temperature and climate of the two countries vary accordingly. 

 These conditions are the result of the distribution of the European 

 Stream which not only conveys warm water to the seas of the 

 British Islands but restricts the cold Labrador current to the 

 shores of North America. 



A well-known meteorologic phenomenon is the retardation of 

 the seasons in the countries surrounding the Norwegian Sea, 

 the North Sea and the Baltic. In the eastern part of Europe, and 

 on the coasts of Scotland, of Ireland, and on the south and west 

 of England, the coldest month of the year is January. In the 

 Shetlands, the Faeroes, the Scandinavian Peninsula, &c., the season 

 is retarded and the coldest month is February. This variation in 



