KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 24. N:0 II. 157 



fair weather and gentle winds from the East. The previous westerly winds had compelled 

 the Baltic stream to keep close to the Swedish coast and had £lled the western part of 

 the Kattegat with inflowing water of 32 and 33 Voo from the Skagerack. But now the 

 Baltic stream under the influence of the easterly wind and of the pressure of the water 

 stored up in the Baltic and the southern part of the Kattegat began to spread rapidly 

 westward beyond the Skaw, overlapping the salter water in the Skagerack, thus producing 

 the formation of a thin superficial layer stretching far to the West, which we have repre- 

 sented as a branch in yellow on the map in plate II. 



Day by day almost from hour to hour we studied the progress of this branch of 

 the Baltic stream by comparing our own observations Avith those of the Danish lightships 

 at the Skaw, La?sö Kende and Trindelen (p. 70 and following). 



The tendency to cleavage in the Baltic stream appears in our section 2 on plate 

 III in the deeper strata of salt water in the Kattegat, which rise in the midst of it like 

 a wall towards the surface and thus form two channels for the outflowing Baltic water. 

 At the surface however it first appears oiitside the Kattegat as far to the North as Station 

 Sn (see pl. I), where a wedge-shaped tongue of salt water appears between the two bran- 

 ches of the Baltic stream. We will noAv foUow the effects of the western branch upon 

 the deeper strata inside and outside the Skaw. By the eastern coast of Denmark it pro- 

 duced an inflowing under-current from the Skagerack entering the Lsesö channel and fill- 

 ing its bottom with a thin rivulet reaching 34 7oo ^^ saltness, until the lOth of February 

 (see section 4A plate III), when it was expelled again as the Baltic stream increased in 

 thickness and left no place for the reaction-current, the La^sö channel being very shallow 

 (see the state of things on Feb. 13 and 14 represented in 4B on the same plate). Sec- 

 tions 4A and B very much resemble the two sections of the estuary of Göta Elf on 

 plate VIII (see p. 74, 75). 



On the outside W. of the Skaw the effect of the outflowing current was to draw 

 water from the depths of the Skagerack basin or inner part of the Norwegian channel över 

 the Danish bank where the saltness and temperature at the bottom increased steadily 

 until the 28th of February, when 35 "/oo salt is observed in the bottom water indicating 

 that oceanwater from the deepest stratum in the Skagerack has reached the height of the 

 reef of the Skaw, i. e. 40 métres, propelled by the reactive force of the surface current. 



The formation of the isosalines 35, 34 etc. in section 1, plate III is, if not alto- 

 gether, at least partly, due to the moving force of superficial stratum of Baltic water 

 represented in the figure bj^ the isosalines 27 — 30 "/oq. 



Judging from the effect produced upon the deep water by the western branch of the 

 Baltic stream, which had been in action not more than a week, we can scarcely overrate 

 (p. 72) the amount of energy stored up in the thin surface currents sweeping alorig the coasts 

 of Sweden and Norway whenever it is made available in producing reaction-streams. But 

 the action of the Baltic current upon the deep strata in the Skagerack and the North Sea 

 must be very difierent in summer and in winter. Therefore the hydrographic condition 

 of the Skagerack will be liable to periodic changes with the seasons. Of this the sections 

 from Hållö to Ö. Risör made by Ekman in July and by us in February (see plate V) 

 give very striking proof. 



