The Ocean and its Wonders, Robert Michael Ballantyne [portable ebook reader txt] 📗

it gives out more smoke and is probably more obtainable on short notice. The experiment of the doorway, moreover, does not require that there should lie two rooms with a door between. We have found that the door of our study, which opens into a cold passage, serves the purpose admirably.

Were we treating chiefly of the atmosphere in this work, it would be necessary that we should enlarge on all the varieties of winds, with their causes, effects, and numerous modifications. But our main subject is the Ocean. The atmosphere, although it could not with justice have been altogether passed over, must hold a secondary place here; therefore we will conclude our remarks on it with a brief reference to hurricanes.

It has been ascertained that most of the great storms that sweep with devastating fury over the land and sea are not, as was supposed, rectilinear in their motion, but circular. They are, in fact, enormous whirlwinds, sometimes upwards of one hundred and fifty miles in diameter; and they not only whirl round their own centres, but advance steadily forward through space.

In the year 1831, a memorable and dreadful series of storms passed over some of the India Islands, and caused terrible havoc, especially in the island of Barbadoes. The peculiarity of these hurricanes was that they ravaged the different islands at different dates, and were therefore supposed to be different storms. Such, however, was not the case. It was one mighty cyclone, or circular storm,--a gigantic whirlwind,--which traversed that region at the rate of about sixteen miles an hour. It was not its progressive, but its rotatory motion, that constituted its terrible power. On the 10th of August it reached Barbadoes; on the 11th, the islands of Saint Vincent and Saint Lucia; on the 12th it touched the southern coast of Porto Rico; on the 13th it swept over part of Cuba; on the 14th it encountered Havanna; on the 17th it reached the northern shores of the Gulf of Mexico and travelled on to New Orleans, where it raged till the 18th. It thus, in six days, passed, as a whirlwind of destruction, over two thousand three hundred miles of land and sea. It was finally dissipated amid heavy rains.

The effect of a hurricane is well described by Washington Irving. "About mid-day," he says, "a furious gale sprang up from the east, driving before it dense volumes of cloud and vapour. Encountering another tempest from the west, it appeared as if a violent conflict ensued. The clouds were rent by incessant flashes, or rather streams, of lightning. At one time they were piled up high in the sky, at another they descended to the earth, filling the air with a baleful darkness, more impenetrable than the obscurity of midnight. Wherever the hurricane passed, whole tracts of forest were shivered and stripped of their leaves and branches; and trees of gigantic size, which resisted the blast, were torn up by the roots and hurled to a great distance. Groves were torn from the mountain-precipices, and vast masses of earth and rock precipitated into the valleys with terrific noise, choking the course of the rivers.

"The fearful sounds in the air and on the earth, the pealing thunder, the vivid lightning, the howling of the wind, the crash of falling trees and rocks, filled every one with affright, and many thought that the end of the world was at hand. Some fled to caverns for safety, for their frail houses were blown down, and the air was filled with the trunks and branches of trees, and even with fragments of rocks, carried along by the fury of the tempest. When the hurricane reached the harbour, it whirled the ships round as they lay at anchor, snapped their cables, and sunk three of them to the bottom with all who were on board. Others were driven about, dashed against each other, and tossed mere wrecks upon the shore by the swelling surges of the sea, which in some places rolled for three or four miles upon the land. This tempest lasted for three hours."

The China seas are the most frequently visited by severe tempests, or typhoons; yet of all vessels, the Chinese junks, as they are called, seem to be least adapted by their build for encountering such storms.

A terrible hurricane burst upon the China seas in the month of January 1837, as we learn from the "United Service Journal" of that year. An English vessel was exposed to it. The sea, rising in mountains around and over the ship's sides, hurled her rapidly on her passage homeward, when suddenly a wreck was discovered to the westward. The order to shorten sail was given, and promptly obeyed; and when they neared the wreck they found her to be a Chinese junk without mast or rudder--a helpless log on the breast of that boiling sea.

There were many Chinamen on deck vehemently imploring assistance. The exhibition of their joy on beholding the approach of the stranger was of the wildest and most extravagant nature; but it was doomed to be suddenly turned to despair, as the violence of the storm drove the ship past the wreck. It became necessary to put her on the other tack, a manoeuvre which the poor creatures construed into abandonment, and the air rang with the most agonising shrieks of misery. But hope was again raised, when a boat was lowered and a rope thrown on board for the purpose of towing the junk to the ship. This intention was frustrated by the windlass breaking. At sight of this one man, in a paroxysm of despair, jumped overboard after the rope; but he missed it. Being a good swimmer, he tried to reach the boat; but his feeble power could avail him nothing in the midst of such raging elements: he speedily sank to rise no more.

Another rope, however, was secured to the junk, and by means of it the rest of the crew (eighteen in number) were saved. Their gratitude was boundless. They almost worshipped the officers, the crew, and the vessel, prostrating themselves and kissing the feet of the former, and the very planks of the latter.

Well-built ships, however, are not always able to withstand the violence of rotatory storms. Instances occur in which the tightest built and best manned ships are destroyed as suddenly as the clumsiest of ill-managed junks. Not many years ago, a vessel was proceeding prosperously on her voyage, when signs of a coming tempest induced the wary captain to reduce, and, finally, to take in all sail. But his precautions were in vain. The storm burst on the devoted ship, and in a few minutes the masts went over the side, and the hull lay a total wreck upon the sea.

These hurricanes or cyclones, although in reality whirlwinds, are so large that man's eye cannot measure them, and it is only by scientific investigation that we have arrived at the knowledge of the fact. The whirlwind, properly so called, is a much smaller body of atmosphere. Sometimes we see miniature whirlwinds, even in our own temperate land, passing along a road in autumn, lifting the leaves and dust into the air and carrying them along in the form of a rotatory pillar. In other regions they exert a power quite equal to the tempest, though in a more limited space, overturning houses, uprooting trees, cutting a track twenty or thirty yards wide through the dense forest as thoroughly as if a thousand woodmen had been at work there for many years.

When whirlwinds pass from the land to the sea they create waterspouts; of which we shall have something to say in another chapter. Meanwhile, we think it may be interesting to give the following miscellaneous information regarding the atmosphere, gathered from the work of Dr Buist, who devoted much earnest study to the subject of atmospheric phenomena.

"The weight of the atmosphere is equal to that of a solid globe of lead sixty miles in diameter. Its principal elements are oxygen and nitrogen gases, with a vast quantity of water suspended in them in the shape of vapour; and, commingled with these, a quantity of carbon in the shape of fixed air, sufficient to restore from its mass many-fold the coal that now exists in the world. Water is not compressible or elastic; it may be solidified into ice or vaporised into steam: but the air is elastic and compressible. It may be condensed to any extent by pressure, or expanded to an infinite degree of tenuity by pressure being removed from it. It is not liable to undergo any changes in constitution beyond these, by any of the ordinary influences by which it is affected."

If the heating and cooling process--which we have described as being carried on between the equator and the poles--were to cease, we should have a furious hurricane rushing perpetually round the globe at the rate of one thousand miles an hour,--ten times the speed of the most violent tornado that has ever carried devastation over the surface of the earth.

The air, heated and dried as it sweeps over the arid surface of the soil, drinks up by day myriads of tons of moisture from the sea,--so much, indeed, that, were none restored to it, the surface of the ocean would be depressed eight or ten feet annually.

We do not certainly know the height of the atmosphere. It is said that its upper surface cannot lie nearer to us than fifty, and can scarcely be further off than five hundred, miles. "It surrounds us on all sides, yet we cannot see it; it presses on us with a weight of fifteen pounds on every square inch of the surface of our bodies--in other words, we are at all times sustaining a load of between seventy and one hundred tons of it on our persons--yet we do not feel it! Softer than the finest down, more impalpable than the lightest gossamer, it leaves the cobweb undisturbed, and, at times, scarcely stirs the most delicate flower that feeds on the dew it supplies; yet it bears the fleets of nations on its wings round the world, and crushes the most refractory substances with its weight. It bends the rays of the sun from their path to give us the aurora of the morning and the twilight of evening. It disperses and refracts their various tints to beautify the approach and the retreat of the orb of day. But for the atmosphere, sunshine would burst on us in a moment and fail us in the twinkling of an eye, removing us in an instant from midnight darkness to the blaze of noon."

We have written a good deal on this subject, yet the thousandth part has not been told of even the grand and more obvious operations of the atmosphere, much less the actions and results of its minor and invisible processes. Were we to descend with philosophers into the minuter laboratories of the world, and consider the permeating, ramifying, subtle part the atmosphere plays in the innumerable transformations that are perpetually going on around and within us, we should be constrained to feel more deeply than we have ever yet felt, that the works of the Creator are indeed wonderful beyond all expression or conception.


CHAPTER SEVEN.


WATERSPOUTS--CAUSES OF--APPEARANCE--ELECTRICITY--EXPERIMENTS--ARTIFICIAL WATERSPOUTS--SHOWERS OF FISH--MR. ELLIS ON WATERSPOUTS IN THE SOUTH SEAS.

We turn back now from the atmospheric to the aqueous ocean. Yet so intimate