July 20, 1900.] 



SCIENCE. 



115 



portion to the abundance of diatoms and vege- 

 table plankton in general, thus confirming the 

 laboratory experiments of Knudsen on this sub- 

 ject. The ' Irminger ' current of Nordenskiold 

 has been delimited more clearly than heretofore; 

 it follows the ' Eeykjanaes Ridge,' skirts the 

 southwest and west shore of Iceland, and then 

 divides into two branches, one of which, turn- 

 ing to the southwest, completes the circuit of a 

 large eddy that centers southwest of Iceland 

 and is characterized by the cyclonic type of ro- 

 tation. The other branch runs northward, 

 hugging the Iceland coast, then eastward, and, 

 north of the center of the island, dives beneath 

 the surface. The complex stratification of the 

 water east of this point, as well as in Denmark 

 Sound and in Baffin's Bay, is illustrated in the 

 memoir by a large number of sections. Petters- 

 son reproduces some of these in his helpful dis- 

 cussion on recent works on this portion of the 

 ocean (Petermann' s Mittheilungen, pp. 1 and 25, 

 1900). 



CURRENTS IN THE NORTH SEA. 



Dr. T. W. Fulton, the scientific superin- 

 tendent of the Fishery Board for Scotland, has 

 reported on the success which has attended hia 

 experiments with numerous bottle-floats to de- 

 termine the currents of the North Sea. (Fif- 

 teenth Ann. Rep., Pt. III.) The circulation 

 throughout the year seems to be that of a single 

 great current which rounds the northern end of 

 Scotland, turns southward, skirting the eastern 

 coast of England to Yorkshire, and then turns 

 eastward to the Danish shore, where it as- 

 sumes a northerly trend. Part of the water 

 enters the Skagerrack, but most of it goes to 

 form the well-known coastal current of South- 

 west Norway. The explanation of this curved 

 path is one of the problems which Dr. Fulton 

 has set himself. The prevailing and dominant 

 west and northwest wind cannot be the imme- 

 diate motor, since it blows almost at right 

 angles to the current with its north and south 

 trends in British and Danish waters. Yet the 

 wind is regarded as the indirect cause of mo- 

 tion. In the southeast portion of the sea there 

 is banking of water by wind stress. Escape for 

 the surplus water is impossible through the 

 Strait of Dover on account of the small size of 

 that opening, and a movement is instituted 



along the steeper surface gradient toward the 

 north along the Danish shore. The remainder 

 of the current curve is explained in largest part 

 as the result of compensation of the movement 

 just described. The earth's rotation may be 

 accorded some share in turning the Gulf Stream 

 water around the northern capes of Scotland, 

 and in causing the clinging of the North Sea 

 current so near to the shore as is actually the 

 case. The influence of tidal streams is ex- 

 cluded by Dr. Fulton, chiefly on the ground 

 that, on the east coast of Great Britain, the 

 north-flowing ebb is stronger than the south- 

 flowing flood. 



THE GULP STREAM DRIFT. 



Does the Gulf Stream Drift persist on the 

 surface at all seasons of the year through the 

 Norwegian Sea? This question, so important 

 to Norwegian fisheries, has, according to Hjort 

 and Gran, been definitely settled. (Report on 

 the Norwegian Marine Investigations, 1895-97, 

 Bergen, 1899.) During the winter the rela- 

 tively warm and dense ' Atlantic ' water is 

 partly displaced by the strengthened Arctic 

 current which runs southeast past the east coast 

 of Iceland, but does not reach the Shetlands. 

 On the approach of summer the polar water re- 

 tires from the surface and is not found south of 

 Iceland. This annual periodicity in the Gulf 

 Stream Drift is accompanied by changes of 

 greater amplitude in time, but their laws have 

 not yet been formulated. Detailed observa- 

 tions on the plankton organisms show that 

 their occurrence has likewise a marked annual 

 periodicity which is associated with that of the 

 currents. Further proofs of a similar relation 

 subsisting between the herring fisheries and 

 current variations of pei'iods ranging from one 

 to several years, have recently been published 

 by Pettersson and Ekman as one result of the 

 international researches of 1894 and 1895 in the 

 North Sea (Bihang till k. Svenska Vet.-Akad. 

 Handl. 1890 Bd. 25, Afd. II, No. 1.) 



hydrography and faunas of spitzbeegen 

 coast waters. 

 A PRELIMINARY review of the material col- 

 lected by the German Expedition to the North 

 Polar Seas in 1898 has afibrded some interesting 

 conclusions as to the conditions of life in the 



