IGO THE OCEAN. 



All the blocks would soon be dissolved by the waves, and not a single 

 fragment remaining to protect the lower strata of the cliff against 

 the destructive action of the waves, the work of erosion would freely 

 resume its course. Devoted to certain destruction, the island is 

 gradually melting in the waters, like an immense crystal of salt. 



The learned do not all give the same degree of confidence to the 

 documents relative to the ancient extent of Heligoland. Some, such 

 as Wiebel,* regard those testimonies of the past as if destitute of 

 sufficient authenticity, and think that the lessening of the island is 

 accomplished very slowly. Others, on the contrary, f more respect- 

 ful to the affirmations of the chroniclers, believe that in the space of 

 five centuries the island has diminished by at least three quarters. 

 However it may be, it is certain that the partially inundated lands, 

 to which the island owes its name, have long since ceased to exist. 

 It is equally certain that towards the end of the seventeenth centur}', 

 an isthmus still united Heligoland to another islet, the cliffs of which 

 rose to about 100 feet in height, like the principal island : two ex- 

 cellent ports, which gave the island a great strategical importance, 

 opened to the north and south between the two rocky masses and 

 their submarine extensions. The eastern island has now disap- 

 peared, and its cliffs are replaced by a few dunes and sandbanks, un- 

 covered at low water : the ports no longer exist, and the ships of 

 war drawing most water, can sail freely where the isthmus still ex- 

 isted less than a century and a half ago. Who would now recognize 

 in this rock of Heligoland, hardly IJ mile long, and about 2000 

 feet broad, the land of which Adam de Bremse speaks in 1072, 

 and which was then " very fertile, rich in corals, in animals, and 

 birds," and which extended, says Karl Miiller, " over a space of 900 

 square kilometres." J In the present day, a few rows of potatoes and 

 a few meagre pastures are the only remains that testify to the an- 

 cient fertility of Heligoland. 



If the sea thus destroys countries bordered all round with rocky 

 promontories, it respects still less the low strands, which in conse- 

 quence of some modifications in the geography of the coasts, or in 

 the relief of the submarine banks, are situated across the cur- 

 rents. In the very front of Heligoland, the shores of Hanover, 

 Friesland, and Holland, which formerly seemed to sink gradual^, § 

 offer the most striking example of this destructive power of the sea. 



* Die Insel Helgoland. f Von Maack Zeitschrift fur die algemeim Erdkunde, 1860. 



X Die Gefahren der schleswigschen West kuste : Natur, March, 1867. 



§ See in Yol. I. the section entitled, The Slow Oscillations of the Terrestrial Soil. 



