86 Ocean Waves 



of a mile may sometimes intervene.* In the presence 

 of such colossal forces, a vessel is like a toy ; nor on reflec- 

 tion is it less than wonderful that an object comparatively 

 so fragile, can make her way amidst them unchecked and 

 unharmed. 



14. By an instrument called the Marine dynamometer, 

 the force of waves at Bell Bock (North Sea) has been ascer- 

 tained to be 1 J tons per square foot, and at Skerry vore 

 lighthouse in the Atlantic, 3 tons per square foot. That is, 

 if a plate a foot square were inserted in the summit of a 

 wave, these pressures would be exerted on it. A practical 

 example of this gigantic force is shown in those occurrences, 

 often disastrous enough, when a ship is " struck " by a sea, 

 that is, when she meets a wave without rising to it. On 

 such occasions, the vessel seems to hang motionless for an 

 interval as if stunned, every bolt and timber quivering from 

 stem to stern. In running or nearly so before a wind, a ship 

 so struck is liable to be forced round by the huge impulse, 

 and if there be gi'eat way upon her, to broach-to, to the 

 almost certain destruction of a spar or spars. Another 

 frequent occurrence is that known. as "settling," common to 

 ships laden with shifting or loose cargo. A fleet of sugar 

 ships coming in port sometimes presents a ludicrous 

 appearance from this cause, the masts of the vessels inclining 

 in various angles and directions. 



An instance of this kind was witnessed by the writer, in 

 the China seas, in 1851. During the prevalence of a dead 

 calm, accompanied however with enormous rollers or ground 

 swell, the result of a typhoon a week previously, the v^essel 

 — which was one of 1,200 tons — having no headway, was caught 



* Latterly, in 1869, waves have been measured in the Engliih Channel, 

 ■with a height of 4.3 feet ; it is probable, therefore, that Dr. Scoresby's estimate 

 for deep ocean waves is sometimes greatly exceeded. The reference to the 

 measurement here stated has unfortunately beon mislaid. Maury, who, in 

 his exhaustive work on the Physical Geography of the Sea, does not treat 

 distinctively of the waves, yet refers in enthusiastic terms to those of the 

 great Southern Ocean. "To appreciate, he says, the force and volume of 

 these polar bound winds in the Southern Hemisphere, it is necessary that one 

 should ' run them down ' in that waste of waters beyond the parallel of 40^ 

 south, where ' the winds howl and the seas roar.' The billows there lift 

 themselves up in long ridaes with deep hollows between them. They run 

 high and fast, tossing their white caps aloft in the air, looking like the 

 green hills of a rolling prairie capped with snow, and chasing each other in 

 sport ; still their march is stately and their roll majestic. The scenery 

 among them is grand, and the Australian-bound trader after doubling the 

 Cape of Good Hope, finds herself followed for weeks at a time by these 

 magnificent rolling swells, driven and lashed by the ' brave west wind ' 

 furiously." — Physical Geography of the Sea, p. 361, 



