266 Proceedings of the Royal Physical Society. 



the sea has overwhelmed, are known as the " Wattenmeer," 

 and figure greatly in Friesian story. 



But what the sea takes away from the islands, it is gradu- 

 ally adding to the mainland. Take, for instance, the main- 

 land opposite Sylt, the largest of all these islands. At one 

 time Tondern was a seaport. But it suffered so terribly from 

 inroads of the sea, that a dyke was built along the line of the 

 outer coast. The result is, that the town is now six miles 

 from the sea, and Hoyer is the village nearest the water. 

 But even Hoyer is getting inland. The land destroyed in the 

 Friesian Islands is swept up against this great bulwark, so 

 that when the tide goes out, a marshy, grassy flat, stretching 

 seaward for half a mile, is laid bare. At high water it is 

 covered, but so slightly, that, though a canal has been cut 

 through it, so as to allow boats or light draught vessels to 

 approach the dyke, yet this canal at full tide has only five 

 feet of water in it. By-and-by this " Wattenmeer " will be 

 laid bare at all states of the tide, and then the land will be 

 " marsch," only to be protected from inroads of the sea by 

 building another dyke farther to the west. Eiderstedt was 

 at one time composed of three islands. By a process of 

 dyking, these three are only consolidated into one peninsula. 

 But this wearing away of the islands, though certain eventu- 

 ally to sweep those which are undyked into the sea, is as 

 nothing to the mighty inundations of the past. In addition 

 to the islands named, there are in the southernmost portion 

 of the Friesian group, near Eiderstedt — the south-western 

 peninsula of Schleswig — Oland, Nordmarsch - Langeness, 

 Appelland, Grode, Habel, Behnshallig, Hamburger Hallig, 

 Hooge, Norderoog, Siideroog, Siidfall, Nordstrandischmoor, 

 Pohnshallig (almost disappeared), Nordstrand, and Pellworm. 

 All of these are inhabited, some of them only by one family ; 

 but with the exception of Nordstrand and Pellworm, none of 

 them are dyked, and hence are frequently inundated, and 

 sometimes covered by the sea. The undyked islets are 

 locally known as ''Hallige" — the plural of "Hallig;" and 

 the inhabitants the " Halligers." 



Two centuries and a half ago, these Hallige and the other 

 islets in their vicinity did not exist ; or, more strictly speak- 



