The idea expressed in the above heading, though commonly held to
be of sacred origin, or as merely a poetical manner of expressing
a commonplace occurrence, may nevertheless be taken literally as
well as figuratively, it being, as a matter of fact, a saying which
has satisfactory groundwork in natural facts. It was recently stated
in evidence before the Commissioners appointed to inquire into the
Herring Fisheries of Scotland, that the practice of pouring a quantity
of oil from a boat on to the surface of the sea during heavy weather
had the immediate effect of calming the waters and relieving the
boat from the danger of heavy broken water. ‘But,’ added one of the
witnesses, ‘although the oil has this effect for a time, the sea
becomes rougher afterwards, and so the advantage of adopting the plan
is practically not very great.’ It is more than probable that this
latter statement can be explained by the law of comparisons. The
oil cast out on the weather-side of the boat effectually assuages
the violence of the waves, which instead of breaking over it, glide
smoothly under it. Presently the film of oil becomes dispersed, and
the waves, again unchecked, appear, by comparison with the late calm,
to be still more formidable. A fresh dose of oil would, however,
again prove advantageous, but the experiment is seldom repeated, and
so the efficacy of the remedy is called into question. The best way
of adopting it is to throw overboard a barrel or skin filled with
oil, and pierced in two places, to allow of the gradual escape of the
contents. This reservoir should be secured by a rope, and kept on the
weather-side of the boat, and renewed as often as necessary. The plan
is frequently adopted, with the best results, by native boatmen in the
Persian Gulf and in parts of the Indian Ocean, where sudden squalls are
apt to spring up.