On the other hand, it is a.s.serted, and we doubt not with equal truth, that many reefs do not seem to increase in size in the course of many years.
When a coral reef has reached the surface, the formation of an island instantly begins; but it necessarily takes a long time ere this island becomes habitable by man. Among the first plants that raise their heads to the sea-breeze is the graceful cocoa-nut palm. This tree is exceedingly hardy, and is found growing on reefs which are so low that at a distance the trees seem to be standing on the surface of the water.
Indeed many of them spring out of the pure white sand, and their roots are washed perpetually by the salt spray. Nevertheless, the fruit of such trees is sweet and good.
Coral islands of the kind we have just described seldom rise more than a few feet above the level of the sea; but most of them are clothed with luxuriant vegetation.
We might easily fill a volume on the subject of the ocean"s inhabitants, small and great; but we think the few to which we have made reference is sufficient for the purpose of showing that one set of creatures accounts for that strange luminosity of the ocean which is seen at times in all marine parts of the globe, while another set accounts not only for the sudden appearance of coral islands in the sea where no such islands existed in days of old, but also, partly, for that circulation of the waters of the ocean which is absolutely necessary to the wellbeing of all the creatures on this earth.
There are other animals in the sea, besides medusae, which a.s.sist in giving luminosity to its waters; and there are other insects, besides corallines, which extract its lime, destroy its equilibrium, and a.s.sist in causing its perpetual motion; but the two species which we have described are the best types of the respective cla.s.ses to which they belong.
CHAPTER SIXTEEN.
VOLCANIC ISLANDS--OPINIONS OF THE ANCIENTS--"ATLANTIS"--INSTANCE OF THE FORMATION OF A VOLCANIC ISLAND--CONCLUSION.
In the last chapter we described the manner in which a certain cla.s.s of islands in the South Seas are formed; in the present we will make a few observations on another cla.s.s, which have sprung up from the bottom of the sea, as if by magic, under the irresistible influence of fire.
There are volcanoes in the sea, as well as on the land; and these volcanoes have in former times up-heaved huge ma.s.ses of land so as to form large islands, while in other cases they have caused islands formerly in existence to subside and disappear.
In the writings of the ancients we find reference made to an island which, if it ever did exist, now exists no longer. It was situated opposite the Straits of Gibraltar, was nearly two hundred miles in length, and was called "Atlantis"--hence the name of the Atlantic Ocean.
Many believe, and with some reason, we think, that this island was not altogether a myth, although much that is said of it is undoubtedly fabulous.
Plato tells us that it was a large island in the Western Ocean, situated before or opposite to the Straits of Gades; and that out of this island there was an easy pa.s.sage into some others which lay near a large continent, exceeding in bigness all Europe and Asia. So far Plato may have told the truth, and from this pa.s.sage it is conjectured that the existence of the continent of America was known to the ancients. But he goes on, immediately after, to draw upon his imagination, and to tell us that Neptune settled on this island, and that his posterity dwelt there for a period of nine thousand years in the midst of fertility and abundance. But, not content with their ample possessions and prolific soil, they went over to Africa and Europe, and even penetrated into Asia, bent on conquest.
Pa.s.sing from this mixture of probable truth and undoubted fable, Plato then a.s.serts that the island of Atlantis finally sank and disappeared.
This may or may not be true, but there is more reason for our crediting the statement than many people would suppose. Certain it is that no such island exists at the present time, but it is believed by some that the Azores, which are volcanic in their formation, are the summits of the mountain ranges of the Atlantis of the ancients.
But the best evidence we have of the possible existence of such an island is the fact that in modern times an island has been _seen_ to rise out of the sea, and, after a time, to disappear, under the influence of volcanic action.
This remarkable event is related by Captain Tillard, an officer of the British Navy, who saw it on the 12th of June 1811, when approaching the island of St. Michael. On this occasion smoke was seen to rise from the surface of the sea, and, soon after, showers of cinders to burst forth.
We cannot do better than give the captain"s own words, as follows:
"Imagine an immense body of smoke rising from the sea, the surface of which was marked by the silvery rippling of the waves. In a quiescent state it had the appearance of a circular cloud revolving on the water, like a horizontal wheel, in various and irregular involutions, expanding itself gradually on the lee side; when, suddenly, a column of the blackest cinders, ashes, and stones, would shoot up in the form of a spire, at an angle of from ten to twenty degrees from a perpendicular line, the angle of inclination being universally to windward. This was rapidly succeeded by a second, third, and fourth shower, each acquiring greater velocity, and overtopping the other, till they had attained an alt.i.tude as much above the level of our eye as the sea was below it.
"As the impetus with which the several columns were severally propelled diminished, and their ascending motion had nearly ceased, they broke into various branches resembling a group of pines. These again formed themselves into festoons of white feathery smoke, in the most fanciful manner imaginable, intermixed with the finest particles of falling ashes; which at one time a.s.sumed the appearance of innumerable plumes of black and white ostrich feathers surmounting each other; at another, that of the light wavy branches of a weeping willow.
"During these bursts the most vivid flashes of lightning continually issued from the densest part of the volcano; and the cloud of smoke now ascending to an alt.i.tude much above the highest point to which the ashes were projected, rolled off in large ma.s.ses of fleecy clouds, gradually expanding themselves before the wind, in a direction nearly horizontal, and drawing up to them a quant.i.ty of water-spouts, which formed a most beautiful and striking addition to the general appearance of the scene."
Such is the description given of this submarine volcano in action; and the crater which was thrown up at the time was about twenty feet above the level of the sea. As Captain Tillard could not, however, delay his voyage to make further observations at that time, the action that subsequently took place is not known; but its results were seen shortly afterwards.
In about three weeks after the date of his pa.s.sing the spot, Captain Tillard returned to it and found an island of about a mile in circ.u.mference, with a height of between two and three hundred feet at its highest point. There was no violent eruption going on, although the craters still emitted smoke. He therefore landed, and, on reaching the largest crater, found it to be full of boiling water, which overflowed and found its way to the ocean in a river of about six yards in width.
This island, however, was not a permanent addition to the world"s archipelago. It sank into the ocean again, and disappeared in October of the same year in which it rose.
In commencing this little book we set out with the intention of rambling hither and thither, among things that relate to the sea, without regard to order. We have carried out our intention; and now, at the close of our task, find that the more we listen to the Ocean"s Voice, the more we find its tale to be interminable, though the reverse of uninteresting.
In these rambles we have sought to treat chiefly of those scientific facts relating to the sea and the atmospheric ocean, which are not so frequently made the subject of books for the young, as are the wild and daring deeds of man upon the surface of the mighty deep.
It is not sufficient that man should become acquainted with the doings of his fellows on the sea. This is but one branch of general knowledge, and a very secondary one compared with that infinitely higher branch which treats of the workings of the Almighty in the ocean; workings which render it what it is--not merely a means of commercial enterprise for man and a home for fish, but also a great purifier and revivifier of the earth and sweetener of the atmosphere. G.o.d is the great first cause of all that is and that operates in the universe. It were an act of presumption to inquire into what we may term the first acts of the Almighty"s power. But there is no presumption--on the contrary there is propriety, as well as the highest gratification of which the human mind is capable--in penetrating through the paths of knowledge up to that first series of second causes which circle like a glory round the fountain-head. We may not put the question, "How did G.o.d create all things out of nothing?" but, all things having been created, it is quite legitimate to inquire how the circles of their manifold operations are carried on, and in what respect the things that be do affect each other.
No book that has of late years issued from the press treats more eloquently and interestingly of such subjects of inquiry than that admirable work of Captain Maury of the United States Navy, ent.i.tled "The Physical Geography of the Sea." Much of the substance of what we have written has been culled from the pages of that fascinating volume. But we have merely plucked one or two leaves, as it were, and presented them to our readers in the hope that they may be tempted by their fragrance to pluck the flower. The mysteries of the atmospheric and aqueous oceans are here treated of fully, yet so agreeably, that one is frequently apt to fancy one is perusing the pages of romance.
In our own little book we have been compelled to skim lightly, and, in many places, to pa.s.s over subjects of great interest.
As for other subjects connected with the sea, of which we may not treat, they are innumerable. Of the sea-weeds that clothe the bottom of the deep with the rich profusion and glowing colours of the gardens of earth--of the myriads of animalcules (besides those we have mentioned) that disport in its waters and fill the abyss with life and lambent fire--of the great whales and other huge creatures that revel in its depths and lash its waters in their terrible might--of these and a host of kindred subjects, our s.p.a.ce forbids our saying more than that the Voice of Ocean has much to tell us in regard to them, and in regard to the provident care of their beneficent Creator.