of the Fishery Board for Scotland. 



361 



of the coast on this subject, but only ascertained that the current 

 off the coast runs north, and south. In the second place, I think a 

 study of the action of the winds over the North Sea, during the period of 

 the experiments, shows that the prevailing winds will largely account for 

 the movement of the water. The circumstance that the course of the 

 tidal movement of flood and ebb has the same range as the movement of 

 the drift bottles appears to be due to the configuration of the coasts, and 

 of the bottom ; the North Sea is practically a basin or bay, and the 

 communication with the Channel seems to have very little connection 

 with the movement of the water. The cross-section at the Straits of 

 Dover is very much less than that of the northern opening between 

 Duncansby Head and the nearest point on the Norwegian coast. As was 

 previously stated, none of the thousands of drifters put away on the east 

 coast have been got south of a line between the Wash and Helder ; and 

 none of those put off between Norfolk and Holland, south of a line 

 between Lowestoft and Helder, although the tidal stream from [the east 

 coast penetrates to the Thames. 



Let us now consider the influence of the prevailing w 7 inds as above 

 described. At North Unst, Shetland, the direction of the wind coincides 

 generally with the direction of the Gulf Stream, or Atlantic current, which 

 impinges on and passes up the western coast of Norway. At Buchan 

 Ness, about 190 geographical miles further south, it blows in much the 

 same direction, and will tend to heap up the water on the south-west 

 coast of Norway. At the Bell Rock, 65 miles (geog.) further south, it 

 blows from the W. by N.; and along the east coast of England from a 

 point somewhat more to the north. The general action of the wind then 

 in the North Sea tends to drive and heap up the surface water on the 

 eastern side, which is very shallow south of the Skagerak. It cannot 

 escape to the south owing to the narrow orifice of the Channel and the 

 shallows, and it, therefore, passes northwards along the coast of Schleswig 

 and Denmark, and joins the current passing up the Norwegian coast and 

 that issuing from the Baltic, sometimes penetrating into the Skagerrak. 

 Pettersson has shown that the strong current that usually flows westwards 

 from the Baltic passes along the south coast of Norway and thence north- 

 wards along the west coast,* and the north-going current along the west 

 coast of Norway is well known. 



It is, I think, chiefly in consequence of this tendency for the heaping 

 up of water on the eastern side of the North Sea and its passage north- 

 wards that water, flowing in from the Atlantic around the North of Scot- 

 land, passes down the east coast of Scotland and England, as previously 

 explained, to take its place. That the wind is a potent factor in pro- 

 ducing this movement is shown by the conditions attending the exceptional 

 reversal of the movement of the water to which reference has been 

 frequently made, and which may now be more fully described. The 

 rotation of the earth is no doubt also of importance. 



4. Reversal of the Normal Current. 



In December 1896, and especially January 1897, a number of drifters 

 were picked up on the east coast, to the north of the place where they were 

 thrown into the water. Some of these belonged to groups which had been 

 put in a considerable time before, and members of which had been pre- 

 viously found to the south, as usual. Others were set adrift in December 

 and January, and rapidly moved northwards. Further, some thrown 



* Journ, Scot. Geogr. Soc, July 1894. 



