We were about a day's sail or so from the Cape de Verd Islands, when one
day, as I was looking out, I saw on the starboard-bow what I was certain
was a shoal of great extent covered with sea-weed. "Land on the
starboard-bow!" I sung out, thinking there could be no mistake about
the matter. I heard a loud laugh at my shoulder. Old Ben Yool stood
there.
"Well, if that is not land, I do not know what is!" I replied. But
still Ben only laughed at me. I was arguing the point, when the
captain, who was on deck, called me aft. I found him with a chart,
which he was showing to Gerard.
"You are not the first person, Harry, who has taken that collection of
sea-weed for land," he observed. "That is the Sargasso Sea. When the
companions of Columbus sighted it, they thought that it marked the
extreme limits of the navigable ocean. We are at the southern edge of
it. Look at this chart; it extends in a triangular form between the
groups of the Azores, Canaries, and Cape de Verds. It is caused by the
Gulf Stream, which, circling round the Atlantic, sends off towards the
centre all the sea-weed and drift-wood collected in its course. Throw
some chips into that tub; now, set the water in motion with your hand.
The current you have created sends off all the chips into the centre of
the tub. You need never forget how this Sargasso Sea becomes covered
with weed. But you will wish to know something about this wonderful
Gulf Stream, which not only produces the effect I have described, but
exerts a very powerful influence, on the climate of many countries, and
on the navigation of the Atlantic, besides causing many other important
results. It is, indeed, one of the most wonderful of all the phenomena
of the ocean. Consider it as a mighty river of warm water flowing for
three thousand miles with scarcely diminished volume, never dying, never
overflowing, over a bottom and between banks of cold water. So little
affinity have its waters with the common water of the ocean, and so
different is their colour, that a distinct line can often be traced
where they pass along. See where it takes its rise in the Gulf of
Mexico, whence it is called the Gulf Stream. Now, mark its course, and
note its effects. Remember, that not only is it warm itself, but it
warms the air which passes over it. It likewise contains much more salt
than the common sea-water. The salt gives it its peculiar deep
indigo-like colour. It runs at the rate of between three and five miles
an hour. It is roof-shaped--that is, higher in the centre than on
either side. This is proved by placing a boat on either side of the
centre, when it drifts off towards the edge nearest to which it is cast
loose. Another peculiarity exists in connection with it. Water
radiates heat far more slowly than does the earth. If, therefore, the
Gulf Stream swept along the ground, it would speedily lose its heat. To
prevent this, it is made to pass over a cushion of cold water, into
which its heat does not readily pass. When, however, its waters wash
any shores, they impart some of their heat to them, increasing the
warmth of the climate, adding fertility to the soil, and making it a
more agreeable abode for man. Now, look at the chart, and observe where
the mighty current leaves its reputed source in the Gulf of Mexico.
Mark it sweeping round the coast of Florida, and glancing off to the
eastward near Cape Hatteras, in the United States, allowing a belt of
cold water to wash the shores of that country during the winter months
of the year. Watch it passing near the coast of Nova Scotia, and in the
summer, not far from that of Newfoundland, where it has undoubtedly
caused the formation of the well-known fishing-banks. This is the way
they have been produced. When the summer sun releases the innumerable
mighty icebergs which have been formed on the shores of the polar
regions, they float away to the south, carried by a current which sets
towards Newfoundland. They bear away with them vast quantities of rock,
and stones, and sand. Meeting the hot water of the Gulf Stream, they
quickly melt and deposit their burdens at the bottom, always about the
same spot which you see marked as the Grand Bank. Now the stream,
taking an easterly course, reaches the 40th degree of north latitude,
when it begins to spread itself over the colder water of the ocean,
washing the shores of Ireland; some going up towards Spitzbergen,
surrounding the Shetland Isles, and other isles in the north; more
rushing up the British Channel; and another quantity flowing into the
Bay of Biscay, and away again towards the south--adding warmth to the
whole of the indented shores of Europe, and at the same time supplying
the deficiency of salt to the waters flowing out of the Baltic and the
Polar basin."
"Thank you, father," exclaimed Gerard; "I now understand why, when last
year we made the voyage to New York, we kept away so far to the
northward. It was to avoid the Gulf Stream, which would have been
setting against us. But I say, father, I want to know why the water
takes it into its head to flow in that way. I suppose there is some
cause for it?"
"Our beneficent Maker undoubtedly formed it for the benefit of his
creatures," returned the captain; "but, as I have often told you, he
brings about his purposes by the laws or causes which he himself has
established. There may be several causes in operation to form this
ocean-stream, though up to this moment learned men have been unable to
decide what they are. Now one theory is advanced, now another. The
shape of the Gulf Stream may have something to do with it. It appears
that it is higher than the rest of the surface, for it is more bulky.
Water will always seek its level. It has thus a tendency to flow
towards the colder and lower water of the poles, feeling at the same
time the effect of the diurnal motion of the globe; while the water of
the poles, to supply its place, flows towards the equator, subject to
the same disturbing cause. Thus the water of the globe is set in
motion. These being hot, tropical waters, remain on the surface, and a
portion of them is forced into the Gulf of Mexico. Here, though they
lose somewhat of their saltness from the fresh waters of the Mississippi
and Orinoco, they gain more heat from these hot streams, and are still
much Salter than the rest of the ocean. Perhaps the impetus may be
given them by the pressure of the currents from the poles. The diurnal
motion of the globe will account for the drift-wood and sea-weed being
cast off on the east or left bank of the stream. There is another cause
for this. From the stream being roof-shaped, any drift which its left
portion took up would have to go up hill to get to the northward.
Therefore, though trees and other produce of the West Indies are found
on the shores of Europe, none are ever picked up on those of America.
And this brings me to the point from which I set out--the cause of the
Sargasso Sea, the centre, it may be called, of this wondrous and almost
inexplicable Gulf Stream."
"But, father, still you have not told us why the Gulf Stream flows in
the direction it does," said Gerard, who generally stuck to the point in
an argument on which he wanted information.
"Men possessed of far more scientific knowledge than I can boast of,
have been puzzled to reply to that question," returned the captain.
"The trade-winds, the diurnal motion of the earth, the expansion of
water by heat, may all combine to force it along and direct its course;
and yet there may be some still more potent cause at work unperceived by
us, perhaps undiscoverable. One thing we know, that it was the will of
the Almighty that so it should flow, for a great and beneficent object;
and that, to effect it, he has employed some potent and sufficient
agent, which, when he thinks fit, he will allow to be revealed to us by
the light of that science which he has given as one of his best gifts to
man. There are, as you perceive on the charts, other currents in the
vast ocean, all set in movement for the sake of benefiting the
inhabitants of the globe. While the warm Gulf Stream runs up to
Spitzbergen, the Hudson's Bay and Arctic currents bring cold water and
icebergs towards the south; and a current from the North Atlantic
carries its cooling waters round the arid shores of western Africa.
There is the great equatorial current from east to west round the world,
and numerous other currents in the Pacific and Indian Oceans, the
influence of which we shall feel during our voyage; and by knowing where
to search for them, and where to avoid them, we can generally make them
serviceable to our object. What I would especially point out to you, my
lads, is the beautiful adaptation of all the works of the Creator to the
great object of the whole. The air and water are kept in motion for the
benefit of man and all living beings. Order everywhere reigns supreme.
Science shows us that storms are regulated by exact laws, and it is only
through our ignorance and blindness that we cannot tell whence they
come, and whither they go. What an admirable system of compensation
exists throughout the universe! Heat, lost by radiation, is quickly
restored; water, lifted up by evaporation, has its place supplied by
colder currents; mighty rivers discharge their waters in vast quantities
into the ocean, and from the far-off regions of the tropics the winds
come loaded with dense vapours, which, precipitated at their sources
with ample and regular measure, supply all their demands. I might
produce numberless examples. As an instance, the whole volume of the
waters of the Mississippi, rushing out at its mouth, find their way back
again in an ever-constant circle to its sources among the far-off lakes
of North America. The Gulf Stream fertilises the earth for the benefit
of man, and it likewise carries food to regions frequented by the mighty
whales. Frequently large shoals of sea-nettles, on which the black
whale feeds, have been met with, borne onward towards its haunts in the
north. The whale itself, it is believed, could not exist in the warm
waters of the stream. Fish, also, are not generally found in it; and
those which inhabit it are of a very inferior flavour. Instead,
therefore, of wandering about the ocean, where they could not be
procured by man, they are driven to the shallow waters near the coast,
where they can easily be caught. It is a curious fact, that the warmer
the water, the brighter are the colours of the fish which inhabit it;
though, as food, they are generally of much less value. While the Gulf
Stream largely benefits the globe, it is at the same time the proximate
cause of shipwreck and disaster, from the storms which it creates, in
consequence of the irregularity of its temperature, and that of the
neighbouring regions, both in air and water. Perhaps nowhere is a more
terrific sea found than when a heavy gale meets the Gulf Stream, when
running at its maximum rate. Many a ship has gone down beneath its
waters. However, I might go on all day telling you curious things about
this same Gulf Stream. One thing more I will mention: people often
complain of the dampness of England. The same cause which so favourably
tempers the cold of our country, creates the dampness complained of. It
is not that our soil is more humid, that marshes exist, or that the
country is not well drained; but it is that the westerly and
north-westerly breezes which prevail, come loaded with the warm vapours
ascending from the tropic heated waters of the Gulf Stream."
"Thank you, father, for all you have told us," said Gerard; "I think I
have learned a great deal I did not know before."
I was certain that I had, and directly afterwards put down, as well as I
could remember, all Captain Frankland had said. The next day we sighted
Saint Vincent, one of the ten islands which form the Cape de Verd group,
so-called from being off the Cape de Verds, on the coast of Africa. The
islands belong to the Portuguese. They produce all sorts of tropical
fruits and vegetables, so that ships often touch here to be supplied
with them. A large number of the inhabitants are black, or of a very
dark hue. Instead of standing directly for the Brazils, Captain
Frankland shaped a course almost across the Atlantic for the coast of
South America. He did this, he explained to Gerard and me, to get the
wind, which generally blows off that coast when the north-east trade
failed us; and to avoid the equatorial calms, in which, away from the
land, vessels are often baffled for days together. I found, after I had
been some time at sea, "That the longest way round is often the shortest
way there," as the saying is. In tropical latitudes, winds from
different quarters blow with great regularity in different places at
certain seasons of the year. The great object of a master is, to find
where the wind is blowing which will be fair for him. The two most
regular winds are the north-east and south-east trade-winds which blow
from either side of the equator, and meet in a wide belt of calms found
under it. There are currents in the air as well as in the ocean; and
Silas told me that he has more than once passed ships at sea right
before the wind--steering north, for instance, while his ship, with an
equally fair breeze, has been standing to the south. Formerly, ships
used to be steered as far south as they could get before the
trade-winds; and then often found themselves baffled for days, if not
weeks together, in the calm latitudes off the coast of Africa, when, if
they had stood boldly across the ocean, as we were now doing, they would
never have wanted a wind move or less fair. Thus it will be seen that
in navigation there are currents in the sea and currents in the air to
be considered, and that it requires a great deal of forethought, and
knowledge, and experience, to take a ship in safety and with speed round
the world. We were bowling along in grand style before the north-east
trade-wind, when Gerard stopped his father in his morning walk on deck.
"I say, father, can you tell Harry and me all about this trade-wind,
which we have got hold of it seems?" said he with a grave look, as if he
wished to become very learned.
"Which has got hold of us rather, I should say, by the way it is
carrying us along," answered the captain, smiling. No one knew Jerry so
well as he did, though he often pretended not to understand at what he
was driving. "You ask a question to which it is rather difficult to
reply in a brief way. Take a piece of paper; draw a circle on it; now,
draw three parallel belts across it--one in the centre, and one on each
side of the centre. Write on the centre belt, `Equatorial Calms;' on
the upper, `Calms of Cancer;' on the lower, `Calms of Capricorn.' The
circle represents the globe; the ends of a line drawn at right angles to
the belts where it reaches the circle, mark the poles. The globe moves
from west to east. Now, suppose a mass of air sent off from the north
pole towards the equator in a straight line, it not partaking of the
diurnal motion of the earth would appear as if it came from the
north-east. Another mass starting from the equator towards the pole in
consequence of the impetus given it, would be going faster towards the
east than the earth, and would, consequently, appear as if it came from
the south-west. This actually takes place, but in the upper regions of
the air. The same exchange takes place between the south pole and the
equator. Now, let us see what becomes of these masses. That which
started from the north pole meets in the air at about the parallel of 30
degrees; the mass which started from the equator meeting with equal
force, they balance each other, and produce a calm and an accumulation
of atmosphere pressing downward, and ejecting from below two
surface-currents--one towards the equator, which are the north-east
trade-winds; the other towards the pole, called the south-west
passage-winds. This moving mass of air, which constitutes the
north-east trade-wind, meets near the equator with another mass which
has been moving on as the south-east trade--meeting with equal force,
they form a calm; and then, warmed by the heat of the sun, they ascend,
one-half streaming off high up towards the south-east--that is, counter
to the surface-current--till it reaches the southern calm belt; another
mass coming from the south-west, where it descends, and rushes as a
north-west surface-wind towards the south pole. We have traced the mass
which started from the north pole. Reaching the southern regions, it is
whirled round till, at the pole itself, a perfect calm is produced, when
it ascends and starts off as an upper current towards the equator; but
meeting another current near the tropic of Capricorn, then descends,
one-half flowing out at the surface, as I have before described, as the
south-east trade, the other towards the south pole. This is the most
beautiful and regular system of atmospheric circulation kept up around
our globe. It has not been ascertained exactly why the masses I have
spoken of take certain directions, but we know the directions they do
take. The red dust we found off the Cape de Verds assists us in certain
degrees. We know some of the agents--the diurnal motion of the earth,
and the sun's heating rays. There are certain counteracting or
disturbing causes from which the surface-winds deviate from the courses
I have described. Some lands are covered with forests, others with
marshes, others with sand. All these may be disturbing causes--so are
lofty mountains. From these causes, and the more powerful effect of the
sun's rays in one place than in another, hurricanes and typhoons occur,
and the monsoons are made to blow--the harmattan on the west coast of
Africa; the simoon, with its deadly breath, in Arabia; the oppressive
sirocco in the Mediterranean. What I have said will explain that
beautiful passage in Ecclesiastes, 1st chapter, 6th verse, which shows
the exactness of the sacred writers whenever they do introduce
scientific subjects: `The wind goeth toward the south, and turneth about
unto the north; it whirleth about continually, and the wind returneth
again according to his circuits.' Who gave Solomon this information? I
doubt if any of his sages possessed that scientific knowledge which has
only been attained by philosophers of late years. Perhaps I may still
more clearly explain to you the cause of the circulation of the
atmosphere. I told you that there were two agents at work--diurnal
motion, and the heat of the sun; but to these may be added the cold of
the poles, which contracts the air. Suppose the globe at rest, and
covered with one uniform stagnant mass of atmosphere; suddenly heat,
cold, and the diurnal motion commence their operations. The air about
the equator would expand, that about the poles contract. Thus two
systems of winds would commence to blow--one above, from the equator
towards the poles; and as thus a vacuum would be left below, a current
would come from the poles to supply its place. The diurnal motion
prevents these currents running in straight lines. That coming from the
poles will appear to have easting in them, and those going towards the
poles westing. Not only, however, is the level of the atmosphere
changed by the heating rays of the sun, but its specific gravity. Thus
the heated current moves more easily and rapidly than the colder; and
the latter, consequently, turns back a portion of what was going towards
the poles, and adjusts the equilibrium of the atmosphere. I have
already shown you the great importance of the circulation of the air in
the economy of nature; and how, among the many offices of the
atmosphere, it distributes moisture over the surface of the earth,
making the barren places fruitful, and tempering the climates of
different latitudes, fitting them as the abode of civilised man. But I
will not pursue the subject further just now. You must do that for
yourselves. Try and remember what I have said, and think about it
whenever you have an opportunity." Jerry and I thanked the captain for
what he had told us, and I, as before, at once dotted it down as well as
I could in my note-book.
Crossing the Atlantic, we sighted a glittering white rock rising fifty
feet out of the water. It was, I found, the Island of Saint Paul's. It
had a curious appearance, standing thus alone in the ocean 500 miles
from the coast of America, and 350 from the Island of Fernando Noronha--
the snowy pinnacle of a submarine mountain. We hove-to close to it, and
a boat being lowered, Mr McRitchie, Mr Brand, Jerry, and I, went on
shore. The whole rock is not three-quarters of a mile in circumference.
Its white colour, we found, was produced by a thin coating of a
substance formed by the washing off of the birds' dung, collected there
in a succession of ages. The rock was covered with birds--my old
friends, the booby and the noddy, I had so often read about. They
stared at us with a stupid look as we pulled up, not at all able to make
us out, and in no way disposed to make way for us. Gerard and I were
for knocking as many as we could on the head; but Cousin Silas would not
allow us, observing that we did not want them for food, and that they
had a far better right to the rock than we had. The booby, Mr
McRitchie told us, is a species of gannet, and the noddy a species of
tern. The first lays her eggs on the bare rock, but the latter
constructs a nest with sea-weed. While the doctor was eagerly hunting
about for specimens of natural history, we were amused by watching the
proceedings of some of the few inhabitants of the rock. By the side of
several of the noddies' nests we saw a dead flying-fish, evidently
deposited there by the male bird. Whenever we succeeded in driving away
any one of the females, instantly a big crab, which seemed to have been
watching his opportunity from the crevices of the rocks, would rush out,
and with greedy claws carry off the prey. One fellow, still more
hungry, ran away with one of the young birds. Another was going to make
a similar attempt.
"I ought to stop that fellow, at all events!" said Jerry, giving Master
Crab a stunning blow. We tied his claws, and presented him as a trophy
to the doctor.
"A fine specimen of _Graspus_" cried our scientific friend, stowing him
away in his wallet.
"A capital name!" said Jerry. "He seemed ready enough to grasp anything
he could lay his claws on."
The doctor said he could find neither a plant nor a lichen on the
island, and only a few insects and spiders, besides the boobies and
noddies. I ought to have mentioned that we did not fail to meet with
the moist and oppressive weather found under the belt of calms under the
equator. Frequently I felt as if I could scarcely breathe, and nearly
everybody was in low spirits and ready to grumble. Jerry and I vowed
that the air was abominable. Cousin Silas stopped us.
"Remember, lads," said he, "what the captain was telling you. If it
were not for them mists, how could the rivers of the north be supplied
with their waters, and the fields of our own land be made fertile?
Thank God rather that you are thus enabled to see more of the wonders of
creation."
I never forgot this remark of Cousin Silas. A delightful writer, now
well-known, describing the subject, calls it "The Circle of Blessing."
[Mrs Alfred Gatty, in her "Parables from Nature."]
Making sail, we soon lost sight of that white-topped rock. Soon
afterward Gerard rushed down one morning at daybreak into our berth,
and, rousing me up, told me I was wanted on deck. Half asleep, I jumped
up, and slipping my legs into my trousers--for no other garment was
required in that latitude--ran with him where he led me forward. I had
scarcely got my eyes open when I found myself seized by two shaggy
monsters; and hearing the sound of a conch shell, I looked up, and saw
before me, as if he had just come over the bows of the ship, a
strange-looking personage, with a glittering crown on his head, a huge
red nose, long streaming hair, and white whiskers as big as two mops.
In his hand he held a trident, and over his shoulders was worn a mantle
covered with strange devices.
"Trite!--where's Trite? Come along, Trite!" he exclaimed, in a gruff
voice--which sounded not altogether unlike that of old Ben Yool's--as he
looked over the bows; and presently he handed up a lady of very ample
dimensions, who certainly, except for a petticoat and a necklace of
shells, I should not have suspected to have belonged to the fair sex.
"Oh, there you are, my lovie! We must be sharp about our work, for we
have so many ships to board that we haven't a moment to lose. Now, if
there are any young shavers who hasn't crossed the middle of my kingdom
before, let them be brought up here in quarter less than no time, or
I'll do--I'll do--I'll do what you shall see."
This was said in a terrifically gruff voice. Before I had time to look
about me, the two monsters had dragged me forward before his marine
majesty and his spouse; and one producing a huge cold tar brush, and the
other a piece of rusty hoop, I found my face paid over with some most
odorous lather. I cried out to Jerry, who I thought, as a friend, ought
to help me; but he pretended to be in a dreadful fright, and when the
monsters ran after him he managed to shove so violently against me that
he sent me head first into a large tub of water which stood at the feet
of Neptune. I was, however, immediately hauled out by the shaggy
Tritons, and after a fresh application of lather, my face was scraped
over with the piece of hoop.
"Douse him--douse the baby again!" shouted Neptune; and from the mode I
was treated, I thought that I should have been nearly drowned, had not
Mrs Neptune, or rather Amphitrite, interfered in a voice which was
intended to be very affectionate, but which sounded as if the poor lady
had a very sore throat, and begged that I might be allowed to return to
my cradle to sleep out the remainder of my watch.
"Oh, good mother, your sex are always gentle and kind," I answered,
determining to jump with the humour of the thing, and to show that I had
not lost my temper, although the ceremony I had gone through was far
from pleasant. "Now, if you'll just leave one of your squires here
aboard, and he'll come aft by-and-by, I'll try if I can fish out a
five-shilling piece from the bottom of my chest, to buy you and your
good man some baccy and rum, to cheer you when you get back to your own
fireside."
"Well spoken, like a true son of the Ocean!" exclaimed Neptune, patting
me on the back. "For that same notion you are free from henceforth and
for ever of my watery realms; seeing also as how you have been lathered
and shaved and crossed the line. So here are three cheers for Mr Harry
Hopeton; and may he live to sail round the world, and to command as fine
a ship as this here craft--and finer, too!"
The crew, at Neptune's beck, on this gave three hearty cheers; and while
the Tritons were chasing down some lads and two or three men, who had
never before crossed the line, I made my escape towards a tub of clean
water, and thence to my cabin, where I very soon removed all traces of
the discipline I had gone through. By the time the captain appeared the
whole ceremony was at an end, and the men were employed in washing down
decks, as if nothing had occurred. It was the third mate's watch; and I
found afterwards that Jerry, who was the chief instigator, had obtained
his leave to have the ceremony take place. The captain, I daresay, also
knew all about it, but said nothing on the subject. Once upon a time
the crew of every ship crossing the line considered it their right to be
allowed full licence to indulge in all sorts of wild pranks; but the
custom got so much abused that many captains have put a stop to it
altogether, while others only allow it among well-tried and trusty
crews. I was not sorry to have had the tricks played on me, because it
contributed to gain me the good will of the people; and I now felt that,
having crossed the line, I had a right to consider myself something of a
sailor.