18 THE NOETH-EAST ATLANTIC. 



THE BALTIC. 



The Skager Rak communicates through the Kattegat with the Baltic, which, 

 like the North Sea, is an inlet of the North Atlantic, though differing from it 

 both in the composition and general character of its waters. The word Baltic, 

 probably of Lithuanian origin, as well as the island of Baltia mentioned by 

 Pliny, is said to mean " white," in reference to its short and foaming crests. By 

 the Germans it was called the East Sea when its southern shores were occupied by 

 the Slavs, and this designation, true as regards Denmark alone, has remained the 

 general name of this inland sea. 



It may in some respects be considered as an affluent of the Atlantic, to whicli 

 it contributes much more than it receives in return. The Neva, Niémen, Vistula, 

 Oder, and the two hundred and fifty other streams of all sizes discharging into the 

 Baltic, send down a volume of water far in excess of what is lost by evaporation. 

 The amount has not yet been directly ascertained, but judging from the mean 

 snow and rain fall of the entire basin, its normal increase may be set down at 

 16,000 cubic yards per second. The whole of this excess must escape to the 

 Atlantic through the Sound and Great Belt, for the level of the Baltic is not, as was 

 till lately supposed, higher than that of the North Sea. An outflowing current 

 has accordingly been detected, running constantly from Copenhagen and Elsinore 

 to the Kattegat, except when neutralised, or even reversed, by the north winds.* 



Nevertheless the currents flowing from the Baltic do not fill the entire depth 

 of their outlets. As in the Dardanelles and Bosporus, there is a smaller back 

 flow of more saline and consequently heavier water, which is distributed through- 

 out the basin of the Baltic. But for this circumstance the Baltic would, in the 

 course of a few centuries, lose its brackish character and become a large river 

 basin, presenting the appearance of an ocean inlet, but forming no part of it. 

 The chemical analysis of the water taken from various depths has determined the 

 existence of the lower back currents in the Soand and Great Belt, constantly renewing 

 the saline properties of the Baltic. In the Great Belt, Meyer, Mobius, Karsten, and 

 Hensen have ascertained that the upper and fresher current is 10, the lower and 

 more salt counter-stream nearly 30 fathoms deep.f The hydraulic works undertaken 

 in the harbour of Copenhagen and the Sound have also aflbrded an opportunity of 

 directly measuring the saline back flow. It has often been observed that of 

 two sailing vessels stemming the surface current in the Sound, here much 

 shallower than in the Great Belt, the larger has much the advantage, being aided 

 underneath by the opposite stream to which its hull penetrates. 



Although the salineness of the great basin is thus constantl}^ maintained, still 

 the gulfs farther removed from the Atlantic receive but a small quantity of salt, 

 the currents growing less and less brackish as they advance from the Skager Rak 



* Course of the upper current in the Sound for 134 days : — 



From the Baltic to the North Sea ...... 86 days. 



From the North Sea to the Baltic 24 „ 



In equilibrio .......... 24 „ 



Forchhammer and Prosilius, Fhihsophical Transactions, 1865. 



t " Expedition of the Powzfraw/V?," 1871. 



