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CHAPTEE XXIII. 



THE HANGGHOW BORE. 



/CONSIDERING that the Hangchow Bore is one of the most striking natural phenomena of 

 the world and that it may be seen practically at our very doors, it is simply astonishing 

 that comparatively few Shanghai residents have ever taken the trouble to make the 

 comfortable houseboat journey to witness it It is all the more astonishing seeing the 

 possibility of the combination of enlightenment, pleasure and sport in one short outing 

 On the other hand it is a sight which very few globetrotters, cultured or otherwise, miss if 

 they have a couple of days to spare. 



As is well known tides are locally affected by coastal configuration as also to a slight 

 extent " by the change of atmospheric pressure." The real cause of a bore or aegre is when 

 the advanced portion of the tidal wave moves so slowly, owing to shallowness or other 

 circumstances, that the succeeding waters gather in a heap. When the estuary of a river is 

 wide, funnel-shaped and shallow, ideal conditions exist for the display of the phenomenon, 

 and more especially so when a strong breeze follows the flood tide. All these conditions exist 

 in perfection in the Chientang river. At its outer extremity the Hangchow Bay is 60 miles 

 wide. It then contracts gradually to within 10 miles at the eastern end. When the tide 

 begins to flow the water rushes in with great force, and just as this channel becomes more 

 and more contracted so is the speed of the tide naturally accelerated. The incoming water 

 assumes a wall-like formation, often from 10 ft. to 15 ft. in height, and sometimes so high as 

 to overflow the banks, the seawall and the low lying hinter land. But high as it is the side 

 of the bore is never so high as the crest of the wave over the deep water. 



The Chinese have an idea that the bore is occasioned by " a tide swelling above 

 another tide." Other accounts represent three successive waves Iriding in, hence the name 

 of the temple at Hangchow, the Tri-wave, from which the spectacle may be witnessed in all 

 its grandeur. An idea of the suddenness of the rise, the force of the flood and the speed at 

 which it travels may be gathered from the well ascertained facts that two-thirds of the flood 

 tide arrives in the river, at any given spot, in a quarter of an hour, and that at Haining the 

 flood only lasts for 3 hours, while the ebb continues for 9. 



The speed with which the water comes in is variously estimated. Father Kennelly, SJ., 

 in Richard's Comprehensive Geography, says that "the immense pressure from behind, and 

 the great height of the tides, which rise to 26 or even 30 feet, impart an extraordinary 

 strength to the current which rushes forward with a roar like thunder, and at a rate 

 sometimes exceeding 6 knots." The venerable missionary, the late Dr. MacGowan, in his 

 paper published in the Royal Asiatic Society's proceedings, January, 1853, estimated the 

 speed of the aegre to be 25 miles an hour. Later day estimates, however, do not put the 

 height of the wave at any such altitude as 26 or 30 feet, and though its speed does often 

 exceed 6 knots an hour it never reaches anything like 25 miles. Captain Usborne Moore, R.N., 



