Emile Sorel

“ If the liquid space is free, the vibrations are gradually extinguished; if they meet an obstacle, there is a shock. If the obstacle is a shore, they form a tidal-wave and raise large billows, while a few miles away from the shore the sea is quiet. When the obstacle is a shoal or a contrary vibration, heavy waves are raised on the surface of the sea; they seem to start from the bottom, and put ships in great danger. The waves produced in both cases are waves of transmission, as also are those which beat on reefs in pleasant weather, and those which prolong the swell after storms. ”

“ If any one interested in scientific matters comes to the shore to study the formation of waves, he will experience some disappointment, for the configuration of the coasts, the eddies, and the currents, modify the phenomena in a thousand ways. ”

“ On the other hand, since each ripple, wavelet, or wave, occupies a given space, and since, as I have already said, a certain number of these are necessary to give rise to a billow or a heavy sea, it is evident that, with a given wind, a billow of a particular dimension can be formed only if a sheet of water extends over a certain area of surface. ”

“ 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? ”

“ A very heavy wind breaks them up and contributes to the formation of a fine dust of salt water or salt spray, which is destructive to vegetation on exposed coasts. The wave proper may, in the English Channel, be about ten feet high, thirty feet or more broad, and eighty feet long; its proportions do not disturb large ships, but it is destructive, in the long run, to port works, and is dangerous to small craft when it breaks. We may estimate that ten waves make a billow. ”

“ If we have a long line of billiard-balls arranged in contact one with another, and give a quick blow to the first one, the last one will roll away. The shock is transmitted from the first ball to the last one, without the intermediate ones suffering any appreciable motion. Marine disturbances caused by direct waves, tides, earthquakes, etc., may in the same way be transmitted through molecules of still water without agitating them. ”

“ We can account for these phenomena and explain the intermittence of the wind-puffs by assuming that the molecules of air, displacing each other, excite a vibratory movement, which gives rise to little undulations following one after another at intervals of a few seconds. ”