44 OF WAVES " TRAVELLING." 



time to note the fact of their approach, when the 

 first wave, sweeping everything in its passage, carried 

 several feet of water into the town. The second 

 swept still further in its destructive course, inun- 

 dating all the low country. The third, rushing on- 

 ward in irresistible fury, overwhelmed everything, 

 submerging the town and twenty thousand of its 

 inhabitants. Vessels at anchor at the mouth of the 

 river were carried inland ; and the sea on retiring 

 left heaps of sand and mud, which rendered it a 

 hopeless task either to search for the dead or for 

 buried property. 



We have spoken of waves " travelling " at such 

 and such a rate, but they do not in reality travel at 

 all. It is the undulation, or, so to speak, the motion 

 of a wave, that travels; in the same manner that a 

 wave passes from one end of a carpet to the other 

 end when it is shaken. The water remains sta- 

 tionary, excepting the spray and foam on the sur- 

 face, and is only possessed of a rising and sinking 

 motion. This undulatory motion, or impulse, is 

 transmitted from each particle of water to its neigh- 

 bouring particle, until it reaches the last drop of 

 water on the shore. But when a wave reaches 

 shallow water it has no longer room to sink to its 

 proper depth ; hence the water composing it acquires 

 actual motion, and rushes to the land with more 

 or less of the tremendous violence that has been 

 already described. 



Waves are caused by wind, which first ruffles the 



