1836.] 385 [Wyckoff. 



The friction of the wind, upon the exposed slope of the swell, produces 

 little irregularities of the surface. These wavelets are driven up the slope 

 to the summit of the undulation. At the same time, the forward slope is 

 more and more protected from the wind, and, because of its inertia, 

 becomes steeper and steeper. Any one who ever saw a sand dune within 

 the limits of the trade winds, has seen the storm wave in permanent form 

 — a long windward slope and abrupt leeward face. The constantly sharp- 

 ening crest of the storm wave, is finally thrown forward and downward 

 with a force proportionate to its weight and speed. "When this storm 

 wave encounters a ship, the vessel cannot rise up the abrupt front. 

 Instead, she checks the progress of the base of the wave, and the crest is 

 thrown forward with tremendous violence, filling her deck and sweep- 

 ing away men, boats and everything movable. The storm wave is, per- 

 haps, no higher than the heavy swell, and only differs from it in shape. 

 Oil changes the storm wave into the heavy swell. How is this done ? 

 The scientific explanations given with great minuteness, that I have seen, 

 would only be confusing to the ordinary mariner. My opinion is : that 

 the oil with its less specific gravity floats on the surface, and spreads 

 rapidly, forming a film, like an extremely thin rubber blanket, over 

 the water. Because of the viscosity of the oil, and its lubricant nature, 

 the friction of the wind is not sufficient to tear this film, and send individ- 

 ual particles rolling up to the summit. At the same time, the molecules 

 of water beneath are protected ; and, although the force of the wind may 

 increase the speed of the undulation as a body, it will be as a heavy swell, 

 and no longer in the shape of a storm wave. This effect can always be 

 obtained at sea, if a suitable oil is used. It has been supposed, that the oil 

 exerts some chemical action in dissolving the foam, as is witnessed, when 

 it stops the frothing of pulp in a paper mill. It is more probable, how- 

 ever, as Dr. Franklin says, that the effect is purely mechanical. 



I have examined one hundred and fifteen reports of the use of oil in 

 storms at sea, published by the Hydrographic Office, and find all the 

 trials were very successful, except four. In these, refined petroleum was 

 used. In one instance, sperm oil was said to have thickened so that it did 

 not spread freely ; but in four others, it acted very well. Fish oil was 

 used 9 times, crude petroleum 3, pine oil 3, linseed 22, lard 5, neat's-foot 1, 

 colza 2, and varnish 3 times. In 58 trials, the kind of oil used is not speci- 

 fied. It is apparent, that the heavier oils are the most efficacious. The 

 result in every instance, where used by a novice, is of extreme astonish- 

 ment at the wonderful effect. One trial seems convincing, and soon it is 

 hoped, the whole profession of merchant officers will be converts, and 

 always go prepared. 



In using oil for this purpose, it is evident that it must be spread well to 

 windward, in order to be efficacious. In consequence, a steamer plung- 

 ing into a head sea, or a sailing vessel on a wind, can derive no benefit. 

 But any vessel driving before a gale, or lying to and making a dead drift 

 to leeward, gets the lull protection of its use. As all vessels, except per- 



PROC. AMER. PHILOS 8QC. XXIII. 123. 2w. PRINTER JUNE 10, 1886. 



