The recent gales have shown that if “Britannia rules the waves” her
subjects are very turbulent and costly. Our shipping interests are
now of enormous magnitude, and they are growing year by year. We
are, in fact, becoming the world’s carriers on the ocean, and are
thus ruling the waves in a far better sense than in the old one. Our
present mercantile rule adds to the wealth of our neighbors instead of
destroying it, as under the old warlike rule.
Everything concerning these waves is thus of great national interest,
the loss of life and sacrifice of wealth by marine casualties being so
great. Some curious old stories are extant, describing the exploits
of ancient mariners in stilling the waves by pouring oil upon them.
Both Plutarch and Pliny speak of it as a regular practice. Much later
than this, in a letter dated Batavia, January 5, 1770, written by M.
Tengragel, and addressed to Count Bentinck, the following passage
occurs:—“Near the islands Paul and Amsterdam we met with a storm,
which had nothing particular in it worthy of being communicated to
you, except that the captain found himself obliged, for greater safety
in wearing the ship, to pour oil into the sea to prevent the waves
breaking over her, which had an excellent effect, and succeeded in
preserving us. As he poured out but a little at a time, the East
India Company owes, perhaps, its ship to only six demi-aumes of olive
oil. I was present on deck when this was done, and should not have
mentioned this circumstance to you, but that we have found people here
so prejudiced against the experiment as to make it necessary for the
officers on board and myself to give a certificate of the truth on this
head, of which we made no difficulty.”
The idea was regarded with similar prejudice by scientific men
until Benjamin Franklin had his attention called to it, as he thus
narrates:—“In 1757, being at sea in a fleet of ninety-six sail,
bound for Louisbourg, I observed the wakes of two of the ships to be
remarkably smooth, while all the others were ruffled by the wind,
which blew fresh. Being puzzled with the differing appearance, I at
last pointed it out to the captain, and asked him the meaning of it.
‘The cooks,’ said he, ‘have, I suppose, been just emptying their
greasy water through the scuppers, which has greased the sides of the
ships a little.’ And this answer he gave me with an air of some little
contempt, as to a person ignorant of what everybody else knew. In my
own mind, I first slighted the solution, though I was not able to think
of another.”
Franklin was not a man to remain prejudiced; he accordingly
investigated the subject, and the results of his experiments, made upon
a pond on Clapham Common, were communicated to the Royal Society. He
states that after dropping a little oil on the water, “I saw it spread
itself with surprising swiftness upon the surface, but the effect of
smoothing the waves was not produced; for I had applied it first upon
the leeward side of the pond, where the waves were largest, and the
wind drove my oil back upon the shore. I then went to the windward
side, where they began to form; and there the oil, though not more than
a teaspoonful, produced an instant calm over a space several yards
square, which spread amazingly, and extended itself gradually till it
reached the lee side, making all that quarter of the pond (perhaps half
an acre) as smooth as a looking-glass.”
Franklin made further experiments at the entrance of Portsmouth Harbor,
opposite the Haslar Hospital, in company with Sir Joseph Banks, Dr.
Blagden, and Dr. Solander. In these experiments the waves were not
destroyed, but were converted into gentle swelling undulations with
smooth surfaces. Thus it appeared that the oil destroys small waves,
but not large billows.
Franklin’s explanation is, “that the wind blowing over water covered
with a film of oil cannot easily _catch_ upon it, so as to raise the
first wrinkles, but slides over it and leaves it smooth as it finds it.”
Further investigations have since been made which confirm this theory.
The first action of the wind in blowing up what the sailors call “a
sea,” is the production of a ripple on the surface of the water. This
ripple gives the wind a strong hold, and thus larger waves are formed,
but on these larger there are smaller waves, and on these smaller waves
still smaller ripples. All this roughness of surface goes on helping
the wind, till at last the mightiest billows are formed, which then
have an oscillation independent of the wind that formed them. Hence
the oil cannot at once subdue the great waves that are already formed,
but may prevent their formation if applied in time. Even the great
waves are moderated by the oil stopping the action of the wind which
sustains and augments them.
Quite recently, Captain David Gray made some experiments at the north
bar of Peterhead, where a very heavy surf breaks over in rough weather.
On a rough day he dropped a bottle full of oil into the sea. The oil
floating out of the bottle, converted the choppy waves over a large
area “into an expanse of long undulating rollers, smooth and glassy,
and so robbed of all violence that a small open boat could ride on them
in safety.”
This result is quite in accordance with what we are told respecting the
ancient practice of the fishermen of Lisbon, who were accustomed to
empty a bottle of oil into the sea when they found on their return to
the river that there was a dangerous surf on the bar, which might fill
their boats in crossing it.
As regards Peterhead, it is proposed to lay perforated pipes across
the mouth of the harbor, and to erect tanks from which these pipes
may be supplied with oil, and thus pour a continuous and widely
distributed stream into the sea in bad weather. The scheme was mooted
some time ago, but I am not aware whether it has yet been carried out.
Its success or failure must mainly be determined by the cost, and
this will largely depend upon the kind of oil that is used. A series
of well-conducted experiments upon the comparative areas protected
by different kinds of oil would be very interesting and practically
useful, for, until this has been ascertained, a proper selection cannot
be made. How long will it last? is another question.
I have frequently seen such tracks as Franklin observed out at sea, and
have climbed to the masthead in order to sight the ship that produced
them, without seeing any. Several of such smooth shining tracks have
been observed at the same time, but no ship visible, and this in places
where no sail has been seen for days before or after. The poet’s
description of “the trackless ocean” is by no means “founded on fact.”
The Plymouth Breakwater contains 3,369,261 tons of stone, and cost
the British Government a million and a half. The interest on this at
4 per cent amounts to 60,000_l._ per annum. If the above statements
are reliable, some of the wholesale oil merchants who read this might
contract to becalm a considerable area of the Channel for a smaller
amount.
Further experiments have been made at Peterhead since the above was
written. The following account, from the _Times_ of those made on
February 27, 1882, is interesting:
“On Monday the long-wished-for easterly gale to test the experiment
of throwing oil on the troubled waters reached Peterhead. It may be
mentioned that the harbor of Peterhead is singularly exposed, and
with an east or north-east gale is very dangerous of approach. Mr.
Shields, of Perth, has laid the oil apparatus to be used in quelling
the troubled waters. It consists of an iron pipe which conveys oil
and extends from a wooden house behind the seawall at Roanhead down
through a natural gullet in the rocks about 150 yards long and about
50 yards beyond the mouth of the gullet into about seven fathoms of
water; at this point the iron pipe is joined to a guttapercha pipe,
which extends across the harbor entrance outside the bar and is
perforated at distances 12½ yards apart. Through the guttapercha pipe
the oil reaches the sea. On Monday the wind was not so strong as to
make the experiment so complete as could have been wished; still,
there was a heavy swell. Early in the forenoon the pumps were put in
motion and the leakage space in the pipe filled; but unfortunately it
was found, soon after the oil began to rise to the surface of the bay,
that the supply in the cask had become exhausted, and those who were
conducting the experiment did not consider themselves at liberty to
order a fresh cask of oil without Mr. Shield’s sanction. But while the
experiment was only partial it was highly satisfactory. At the same
time, the film did not extend sufficiently far to prevent the waves
forming and curving to broken water. As soon, however, as they reached
the oil-covered neck the observers from the pier-head could easily
discern the influence at work. Waves which came in crested gradually
assumed the shape of undulating bodies of water, and, once formed, they
rolled unbroken towards the breakwater. On Wednesday morning there
was a heavy sea at the north breakwater. The oil valves were opened,
and immediately the effect was manifest. The waves, which had before
clashed with fury against the breakwater, assumed a rolling motion and
were quite crestless. Indeed, it was admitted that the oil had rendered
the entrance comparatively safe, _but the effect was not so abiding as
could have been wished_.”
As regards the want of duration there noted, I venture to make a
suggestion.
Oils vary so greatly in their rate of outspreading over water and the
character of the film they form, that some years ago Mr. Moffatt,
of Glasgow, proposed to use these differences as a test for the
adulterations of one kind of oil with other and cheaper kinds.