496 THE POPULAR SCIENCE MONTHLY. 



sea in which they are formed. Thus the largest surface of water to 

 be found on the earth is in the latitude of the Cape of Good Hope ; 

 and the strongest waves are met in the neighborhood of this cape. In 

 the Mediterranean the wave is short. 



In all ages men have sought for means of calming the agitation of 

 the waves, which is so prejudicial to shipping. The best means hith- 

 erto employed has been that of breakwaters, the operation of which is 

 too well known to need description. It may be added that floating 

 wave-breaks, such as would be constituted by a large number of spars 

 or planks left to drift, afford a perfect amelioration of the agitation of 

 the waves. Hitherto engineers have applied their efforts only against 

 the larger waves. Why not attack the evil in its origin ? Why not 

 take up the ripples and the wavelets, and oppose them with floating 

 ripple-breaks ? Such breaks might be made with twigs, saw-dust, or 

 soot, etc., and experiment has proved that they will be efficacious. The 

 needles of ice which form in cold weather on the surface of the water 

 are excellent natural wavelet-breaks. Generally, every cause hinder- 

 ing the formation of wavelets appeases the agitation of the waves. 

 Thus a rain, every drop of which breaks a ripple, calms the sea to a 

 certain extent. Sailors know this. Billows have been fought against 

 with ordinary wave-breaks. Wavelets may be destroyed by employing 

 light bodies, ripples with dust, microscopic ripples with an infinitely 

 fine powder. A liquid will serve the end admirably. Oil is the best 

 of all agents for the purpose. It has the property (to which capillarity 

 is probably not foreign) of spreading over the water as a pile of billiard- 

 balls spreads over a well-polished marble table. Its molecules form as 

 many floating microscopic pebbles, in the intervals between-which the 

 ripples break, as the billows break upon the shingle of the coasts. Oil 

 thus acts as a lubricant, attenuating the friction of the wind. Capil- 

 lary phenomena, due to the minuteness of the intervals between the 

 oleaginous molecules, intervene to divide up and draw off the surface 

 of the water and completely neutralize the force of the wind. All of 

 these causes together may give us the reason of the efficacy of oil in 

 destroying waves. 



It should be understood that all the means of restraining the agita- 

 tion of waves here indicated are good only against direct waves due 

 to the formation of ripples. They have but slight influence on waves 

 of transmission, which are due to other causes. Oil may appease the 

 billows, but the swell will continue. Translated for the Popular Sci- 

 ence Monthly from La Nature. 



