156 OUR HERITAGE THE SEA 



the attraction of our satellite must, on the open ocean 

 at least, be sufficient to overwhelm any vessel it meets 

 on its way. Yet nothing of the kind ever happens. 

 It is true that occasionally huge knolls of water, travel- 

 ling at a great rate, are met with far out at sea, 

 causing panic on board the vessels they meet with, but 

 seldom do much damage. It is equally true that these 

 sudden swellings of waters are usually characterized 

 as " tidal waves," although investigation proves that 

 they are nothing of the sort cannot be, because while 

 the tidal waves are perfectly regular in their incidence, 

 these great uprisings of ocean are abnormal, and are 

 therefore undoubtedly due to some cosmic cause, such 

 as a submarine earthquake or eruption of a deep-sea 

 volcano. Yet in certain lonely, out-of-the-way isles 

 of the sea, such as Ascension, St. Helena, and Tristan 

 D'Acunha, there occurs at irregular intervals a sudden 

 shoreward rush of the ocean, stupendous rolling hills 

 of water which threaten to engulf the land. No one 

 who has ever witnessed the occurrence of the " rollers," 

 as they are somewhat feebly termed, can have any idea 

 of their terror-striking aspect. They occur when the 

 sea is fairly smooth, just furrowed by the usual winds, 

 and there is apparently no reason to expect anything out 

 of the common order of things. Then suddenly, without 

 any warning, will appear in the offing a huge wave 

 reaching from one side of the horizon circle to the 

 other, travelling shoreward at a tremendous rate of 

 speed. Vessels at anchor lie right in its fateful path, 

 and no seamanship may avail to enable them to avoid 

 its awful impact. The few minutes intervening between 

 its first appearance and the shock of its arrival seem 

 like hours, but they pass ; it strikes, and the bay is 



