"WAVES, THEIR MODE OP FORMATION. 25 



(ebb and flood); and partly permanent, though of unequal 

 strength and rapidity at different periods (oceanic currents)." 



Who has ever sojourned on the coast, or crossed the seas, and 

 has not been delighted by the aspect of the waves, so graceful 

 when a light breeze curls the surface of the waters, so sublime 

 when a raging storm disturbs the depths of the ocean? 



But it is easier to admire the beauty of a wave than clearly 

 to explain its nature, so as to convey an accurate or sufficiently 

 general conception of its formation to the reader's mind. Those 

 who are placed for the first time on a stormy sea, discover with 

 wonder that the large waves which they see rushing along with 

 a velocity of many miles an hour do not carry the floating body 

 along with them, but seem to pass under the bottom of the ship 

 with scarcely a perceptible effect in carrying the vessel out of 

 its course. 



In like manner, the observer near the shore perceives that 

 floating pieces of wood are not carried towards the shore with 

 the rapidity of the waves, but are left nearly in the same place 

 after the wave has passed them as before. JSTay, if the tide be 

 ebbing, the waves may even be observed rushing with great 

 velocity towards the shore, while the body of water is actually 

 receding, and any object floating in it is carried in the opposite 

 direction to the waves out to sea. 



What, then, is wave-motion as distinct from water-motion ? 

 The force of the wind, pushing a given mass of water out of its 

 place into another, dislodges the original occupant, which is 

 again pushed forward on the occupant of the next place, and 

 so on. As the water-particles crowd upon one another, in the 

 act of going out of their old places into the new, the crowd 

 forms a temporary heap visible on the surface of the fluid, and 

 as each successive mass is displacing the one before it, the un- 

 dulation or oscillatory movement spreads farther and farther 

 over the waters. Wave-motion is, in fact, the transference of 

 motion without the transference of matter : of form without the 

 substance, of force without the agent. 



The strongest storm cannot suddenly raise high waves, they 

 require time for their development. Fancy the wind blowing 

 over an even sea, and it will set water-particles in motion 

 all over the surface, and thus give the first impulse to the- 



