ON THE MOTION OP WAVES. 



the bottom for half an hour. It was sunk by means of the deep 

 sea-sounding lead *. 



[EDITOR. 



SECTION VIII. 

 On the Motion of Waves , and the Effects of Oil In quieting them. 



IT will easily be conceived that the waves rise higher or lower, 

 according to the power of the original moving force ; for the more 

 water is displaced by that force, the greater quantity of it must be 

 elevated above the -usual level ; and of course the breadth of the 

 waves is likewise greater, 



It seems to be pretty well determined from a variety of experi. 

 ments and observations, that the utmost force of the wind cannot 

 penetrate a great way into the water; and that in great storms the 

 water of the sea is slightly agitated at the depth of 20 feet below 

 the usual level, and probably not moved at all at the depth of 30 

 feet or five fathoms +. Therefore the actual displacing of the 

 water by the wind cannot be supposed to reach nearly so low ; hence 

 it should seem that the greatest waves could not be so very liigh as 

 they are often represented by accurate and creditable navigators. 

 But it must be observed that in storms, waves increase to an enor- 

 DIOUS size from the accumulation of waves upon waves; for as the 

 wind is continually blowing, its action will raise a wave upon another 

 wave, and a third wave upon a second, in the same manner as it 

 raises a wave upon the flat surface of the water. In tact, at sea, a 

 variety of waves of different sizes are frequently seen one upon the 

 other, especially whilst the wind is actually blowing. And when it 

 blows fresh, the waves, not moving sufficiently quick, their tops, 

 which are thinner and lighter, are impelled forward, are broken, 

 and turned into a white foam, particles of which, called \hespray, 

 are carried a vast way. 



Waves are circular, or straight, or otherwise bent, according as 

 the original impression is made in a narrow space nearly circular, or 

 in a straight line, or in other configurations. In open seas the waves 



* Phil. Trans. 1770. Vol. Ix. p. 39. 



+ Boyle's works, folio edition, vol. iii. Relations about the bottom of .the 

 fen; sect. iii. 



2 A 4 



