The Ocean and Its Wonders

by R. M. Ballantyne

In “The Tempest,” an interesting work on the origin and phenomena of wind, published by the Society for Promoting Christian Knowledge, a curious and simple experiment is described, whereby the existence of upper and under currents of air and the action of land and sea breezes may be clearly seen and understood. We quote the passage:—

“The existence of the upper and under currents of air which mark the phenomena of the trade-winds, and of land and sea breezes, may be beautifully illustrated in two adjoining rooms, in one of which a good fire is burning, while in the other there is none. If the door between the two rooms be thrown open, the cold air will enter the heated room in a strong current, or, in other words, as a violent wind. At the same time the heated air of the warm room ascends and passes the contrary way into the cold room, at the upper part of the same doorway; while in the middle of this opening, exactly between the two currents, the air appears to have little or no motion. The best way to show this experiment is to introduce the flame of a candle into the doorway between a hot and a cold room. If the flame be held near the bottom of the doorway, where the air is most dense, it will be strongly drawn towards the heated room; and if held near the top of the door it will be drawn towards the cold room with somewhat less force; while midway between the top and bottom the flame will be scarcely disturbed.

“There is also another pretty experiment which illustrates well the theory of land and sea breezes. Take a large dish, fill it with cold water, and in the middle of this put a water-plate or a saucer filled with warm water. The first will represent the ocean, and the latter an island made hot by the rays of the sun, and rarefying the air above it. Take a lighted wax candle and blow it out; and, if the air of the room be still, on applying it successively to every side of the saucer, the smoke will be seen moving towards the saucer and rising over it, thus indicating the course of the air from sea to land. On reversing the experiment, by filling the saucer with cold water (to represent the island at night) and the dish with warm water, the land breeze will be shown by holding the smoking wick over the edge of the saucer; the smoke will then be wafted to the warmer air over the dish.”

We have just tried the first of these experiments, with complete success. We would, however, recommend a piece of twisted brown paper, lighted and blown out, instead of a wax candle, because 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.