SAND-BANKS OF THE BALTIC. 179 



hafF of Courlande, is much freer from alluvium, and the Nehrung 

 which defends it is a narrow sand-bank about 68 miles in length. 

 The central liaff, known under the name of the Frische Haff, is pro- 

 tected by a bank similar to that of Courlande, but still more regular- 

 All the western part of the estuary has already been filled up by the 

 alluvium of the Vistula, the Waters of which have opened a way 

 through the bank. This embouchure has often changed its place. 

 Till the fourteenth century it was to the north of the present passage, 

 near Lochstildt (town of the gap or grau). Later, it opened at 

 Rosenberg, nearly in the middle of the dike. To preserve their 

 commercial monopoly, the merchants of Dantzig filled this opening 

 up by sinking five ships there; but another passage was formed 

 almost immediately at a little distance towards the north, near the 

 castle of Balga. More greedy than wise, the Dantzigers again at- 

 tempted to arrest the waters of the Vistula, and closed the passage 

 of Balga. It was then that the Nehrung was broken before Pillau. 

 Since this period the passage has not been sensibly displaced, and 

 Pillau has always remained the port of the Frische Haff. To the 

 north of Dantzig a curious bank, 20 miles long, unites the main- 

 land to the picturesque island of Hela (the holy). Doubtless the 

 ancient inhabitants of the country experienced a sentiment of reli- 

 gious terror at the sight of the rude waves which assail this wooded 

 hill, united to the continent by this narrow dike of sand stretching 

 far away into the dim distance. 



It is to the same order of phenomena that we must refer the 

 gradual prolongation of tongues of land, which, bathed on either side 

 by a current, project to a great distance into the open sea, owing to 

 the fresh materials which each new tide adds to the terminal point. 

 It is thus that in less than 16 years Cape Ferret has advanced about 

 3 miles across the channel by which the basin of Arcachon communi- 

 cates with the open sea. In 1768 the Cape was almost to the west of 

 the basin properly so called. In the latter part of the eighteenth 

 century, and at the commencement of the present, the winds from the 

 north, which blow in those parts more frequently than the other 

 atmospheric currents, had caused the dunes of the promontory to ad- 

 vance each year in a southerly direction, while the surf from the 

 open sea, and the ebb of the basin, incessantly added fresh masses of 

 sand to the point. In 58 years, from 1768 to 1826, the Cape length- 

 ened by above three miles towardsthe south-east, with an average speed 

 of 94 yards per year, or about 8 to 10 inches per day. The point in- 

 creased, so to say, visibly ; but a few years later the passage had sud- 



N 2 



