210 SUCCESSFUL USE OF OIL TO CALM ROUGH SEAS. 
approach the bows of the boat, over which oil should be 
poured, or, better still, a bag of oil floated some yards in front 
of the boat, attached by a light line to the anchor so that the 
oil may spread all round. In the second case, when the boat 
is running with the wind and waves, the danger would be lest 
a wave should follow on so quickly as to break over the stern 
of the boat and overwhelm her. Oil poured over the stern 
of the boat will, to a certain extent, quiet these following 
waves, and prevent such a risk. It has to be noted that the 
calming effect of the oil is greatest in deep water, and the 
results are more marked and beneficial at sea than in surf or 
breakers, where it is shallow water. In surf, or waves break¬ 
ing on a bar in shallow water, the effect of oil is uncertain, 
as nothing can prevent the larger waves breaking under such 
circumstances, but even here oil is of some service. 
An official report upon the use of oil at sea for modifying 
the effect of breaking waves, is given in a memorandum from 
the Admiralty, of 16th June, 1886, giving a report by Captain 
Chetwynd, of 80th September, 1884, to the National Life¬ 
boat Institution upon this subject, with directions for the 
application of the oil. Admiral Cloue, of the French Navy, 
gave to the Academy of Sciences, 6th June, 1887, the results 
of more than 200 experiments that had been made upon the 
subject, mainly in England and America, and he concludes 
that there can no longer be any doubt that oil has a most 
efficacious result in calming storm-tossed waters, and thus 
saving vessels in danger of foundering at sea. He says fish 
oils appear the best for the purpose, mineral oils owing to 
their lightness are less effective. 
The United States Hydrographic Office, in calling attention 
to the subject in 1887, states that there is now ample evidence 
that the use of oil is of considerable service in lessening the 
effect of dangerous seas. It is noticed that the “ slick ” made 
by the oil has extended as far as thirty feet to windward, 
and it is concluded that the oil is of use when a vessel is 
reaching ahead at a speed of eight online knots an hour, with 
a beam wind and sea. 
Much of the action of the oil seems to be simply as a 
direct lubrication between the surface of the water and the 
air, reducing the friction between them. This friction is 
very considerable ordinarily, and much greater than at first 
appears possible ; and it is shown by the heavy scud seen 
flying in a gale at sea, which is water lifted up and carried a 
long distance by the friction of the air passing over the surface 
of the sea. The crests of waves are torn off and carried away 
by violent gusts of wind ; and a great source of danger in a 
