48 THE OCEAN. 



distance of several miles. But the surf produced by tlie currents 

 and the dashing of the waves, where the sea is not frozen, gives 

 the most varied directions to the crevasses ; in some places they are 

 parallel, while in others they intersect one another irregularly or 

 radiate towards all points of the horizon. 



Ice very rarely covers the surface of the sea while the water is 

 much agitated. Tempests or rapid currents retard, or even com- 

 pletely prevent, the formation of the ice-sheet. Thus, while on the 

 east, where the sea is calm, the island of Oesel is, on an average, 

 united to the mainland during 130 days of the year by a layer of ice 

 sometimes attaining a thickness of more than three feet, and serving 

 as a high road for sledges ; the western cliffs, against which the surges 

 strike, are, on the contrary, only bordered by a narrow fringe of ice. 

 On the promontory of Muhha Ninna the waves always break with 

 fury, and this extreme agitation of the water lasts during the whole 

 winter, preventing the appearance of the least particle of ice ; indeed 

 the peasants of the island say that they have never seen any near 

 this point.* 



Every year, a considerable part of the Baltic is covered with ice. 

 Almost all the Gulf of Bothnia and the entire coast-line of the Gulf of 

 Finland is changed into a white and immovable surface, the islands 

 and islets are encircled by a zone of ice-floes, more or less wide, whilst 

 the straits of a slight depth are similarly obstructed. Every winter 

 Finland is reunited to Sweden by a bridge of ice, pierced here and 

 there by the innumerable rocks of the Oeland archipelago. This solid 

 crust then becomes for many months the highway between Sweden 

 and Russia. The Baltic, like the Polar ice-fields, has its piled-up 

 masses of ice resembling turrets, pyramids, and obelisks built upon the 

 sea ; from these fields, also, broad masses are detached from their edges 

 to float towards the south with the current, then breaking with a 

 loud crash, are similarly reduced into scattered pieces ; and in a few 

 days after the commencement of the thaw only thin fragments 

 remain, tossed here and there by the waves. 



During the last few centuries the Baltic Sea has never been 

 entirely covered with a field of ice. But the chronicles inform us 

 that in 1323 the southern part of the basin was completely frozen 

 over, and during six weeks travellers from Copenhagen repaired on 

 horseback to Lubeck and Dantzic ; and temporarj^ hamlets were even 

 erected on the ice at the intersection of the roads. During the 

 winters of 1333, of 1349, 1399, and 1402, the same phenomena of 



* Ton Sass, Bulletin de V Academic de Saint Petersbourg, t. ix. p. 1G6, &c. 



