Page:Popular Science Monthly Volume 72.djvu/119

Rh by way of the water-route we have already described. In 1905 the total trade of the port amounted to 17,496,980 Haikuan taels. Our interest in these facts in the present connection lies in this: that this ancient and important city, whose population is now about 350,000, owes its very existence toward the southwest to the construction of the great sea-wall, called by the natives the "bore wall."

It is probably true that some thousands of years ago the great flat area now forming a considerable part of the province of Chekiang and Kiangsu was under water and that the Yangtse, gradually increasing its delta, reclaimed the land. The inhabitants, to assist the river in its land-forming process, built sea-walls, using the various islands as corner-stones. The wall or dyke confining the waters of the Haining-Hangchow canal is probably one of these early structures, which has better withstood the ravages of time and tide. As these walls were multiplied and extended, they caused the projecting north point formed by the alluvial deposits of the Yangtse and the Ch'ien-tang Kiang to extend seaward, thus forming the present funnel-shaped mouth of the latter river, as already noted, and obstructing to a considerable extent the progress of the ocean tide, the northern promontory deflecting it inwards and the shoals causing it to heap up into an increasingly powerful wave—the forerunner of the present bore. Against this rush of water the poorly constructed dykes were insufficient and the people along the shores of Hangchow Bay, especially on the northern side, frequently suffered great losses.