IN former chapters we have seen that the ocean, by the process of evaporation and rain, supplies alike the little rills skipping down the mountain side, and the mighty rivers rolling their great torrents back again into its bosom. We have traced the tiny stream and the swelling flood, and in our last chapter we gazed together on rapids, and tarried long over that greatest of all watery wonders, the mighty Falls of Niagara.
Before we come to the ocean itself, we must say a little about those small or large collections of water which we call lakes. These may be said to take a similar place on the land that islands take on the ocean. You know an island is land completely surrounded by water. Now a lake is water surrounded by land. You must mark the difference between lakes, lagoons, and pools. Lagoons are the overflowings of rivers, or occasional encroachments of the sea; pools are mere collections of rainwater, and generally dry up in summer; whereas true lakes are constantly supplied by streams flowing into them, or by springs gushing up from their bed. Some are very small, covering not more than five square miles, while others are so large as to be called inland seas; of these the Caspian Sea is the most remarkable, and covers 160,000 square miles. Then, again, some are very ancient, indeed they are supposed to be as old as, and once to have been part of the ocean itself, which originally covered the surface of the whole earth. Others are more modern, and have been formed by various causes. Many by the action of great volcanic fires, earthquakes upheaving some parts, and causing vast tracts in other places to fall into immense cavities, caused by internal fires. These great cavities would soon fill up with water draining from the surrounding country, and become lakes. Sometimes there will be a great land avalanche, or land slip, as it is sometimes called, across a stream. Should there be high hills on each side, the water will accumulate till it either sweeps away the obstruction or rises above it, in which case a lake will be the result.
Lakes may be divided into four classes: 1st—Those which have no apparent inlets or outlets streams running into or out of them. These are fed chiefly by underground springs, which, as I told you in a former chapter, may come from a great distance and from much higher ground, but which have never before been able to find an outlet. Some of these are very salt. There is one in Asia called Tuzla. It is narrow, but fifty miles in length, and its waters are so salt that no fish or animal can live in it. Even wild fowls are afraid to venture upon its waters, for if they do their wings soon become stiff by a coating of salt forming on them.
2nd-Another class have streams running out of them but none running in so as to supply them with water. These are generally much above the level of the sea, and derive all their supply from underground springs. There is one on Mount Rotonda, in the island of Corsica, which is 9,000 feet above the level of the sea. The source of the great river Volga may be traced to a lake of this kind.
3rd—A third class have streams or rivers running into them but have no outlets. These lakes are most peculiar of all, but they are very rare. There is one in Italy of a remarkable kind. It is now called Celano, but its ancient name was Fucinus. It covers over 100 square miles, and has no natural outlets for its waters through the hills by which it is surrounded. During the time of the Roman Empire it often rose so high as to destroy an immense tract of fertile country, and the Roman Senate was petitioned to drain it through one of its surrounding hills. The Emperor Claudius at length undertook this tremendous work. For eleven years no fewer than thirty thousand men were engaged in cutting a large tunnel through one of the hills. Pliny, the great Roman historian, tells a sad tale of the cruelty and barbarity of the Roman people, so much extoled for their refinement and intelligence. When everything was ready for letting off the water, a grand naval spectacle was exhibited on it, something like one of our grand naval reviews, only a great number of condemned criminals were ranged in separate fleets, and obliged to engage in earnest combat and to destroy each other, instead of a sham fight, for the entertainment of the court and an immense number of spectators, who covered the neighboring hills. A line of well-armed vessels and rafts loaded with soldiers, surrounded the scene of action to prevent any of the poor doomed victims from escaping. When, however, the savage diversion was ended, and the operations for the opening of the tunnel commenced, the emperor was very near being swept away and drowned, by the sudden rush of the waters towards the vent. The tunnel proved a failure, as it speedily choked up and the lake rose so much as to cover 10,000 acres of fertile soil, when it was again reopened, and means adopted to keep the waters to a low level. There is a great lake called Uramea on the Persian frontier, three hundred miles in circumference and completely land-locked by most beautiful mountains. Though constantly fed by numerous currents, it has no outlet, yet there is no increase of its waters, but a gradual decrease, the waste by evaporation being greater than the supply. This lake is intensely salt. There is a remarkable lake of this kind, the Lake Van, of Armenia, which is much celebrated for its beauty by eastern writers, both in prose and verse. It occupies the bottom of an immense volcanic ampitheatre, is upwards of 240 miles in circumference, and receives the waters of eight rivers, without having a single stream to carry off any of its waters.
But by far the most remarkable of this kind are the Caspian, the sea of Aral, and the well known Dead Sea. The majestic Volga, 1,900 miles long, pours its vast volumes of water into the Caspian, together with the Kur, the Ural, and the Aras, yet with all these vast and constant supplies, there is not a single stream that leaves its shores. So great, however, is the power of evaporation that this has now ceased to be a wonder.
To most of my young readers the Dead Sea, in the south of Palestine, will be the most interesting of all lakes. It is emphatically the lake of the Bible. The river Jordan, which has a history so thrilling, so truly wonderful, so mixed up with many of the most important events in Scripture, flows into this lake. Crossing the Jordan was Israel's last day's march, after forty years' wandering in the wilderness. What a solemn sight that must have been! When Jordan was at its highest—its banks overflowing—there stood the ark of God, in the midst of the river, surrounded by the priests, the waters reared up into a great heap, far above them, while the whole people passed dry shod over! As you know the Dead Sea is very small—not more than about nine miles wide, and thirty-nine miles long. During the rainy season when Jordan "overflows her banks" the lake rises from ten to fifteen feet, and the length of it increases at least two miles. The lake lies in a deep cauldron surrounded by lofty cliffs of naked limestone rocks, the western portion of which rises 1,500 feet above the water, and the eastern portion 2,500 feet. As you all know the consumed cities of Sodom and Gomorrah are supposed to be covered by its waters. It is exceedingly salt; so much so, that no life can exist in it, and it is impossible for people to sink in its waters. Sterility and deathlike silence prevail upon its shores. In some places it is 1,800 feet deep, 'but varies very much in different parts; and it is said that large hewn stones can be clearly distinguished at its bottom, the remains of the destroyed cities.
The aspect of the Dead Sea, the deep mountain ravine in which it rolls, the wilderness—the silence, solitude, and universal barrenness, together with the remembrance of the ancient and terrible disaster, make a deep impression on the mind of the visitor.
The most remarkable of all the features of the Dead Sea is its bed being so much below the level of the Mediterranean Sea, which has now been ascertained to be over 1,300 feet.
4th—The last class of lakes are such as have streams flowing both into and out of them, and these are by far the most numerous. In all probability the largest of these were formerly connected with the main ocean, as some of the large lakes in Russia, and the well-known and important North American lakes. Lakes Superior, Huron, Erie, and Ontario are all connected by channels and their surplus waters are carried off by Niagara river over the falls, and into the St. Lawrence. All these magnificent inland seas are composed of beautiful fresh water, and an enormous traffic is carried on over their vast expanse.
Floating islands are amongst the wonders of water. Some are to be found in the lakes of Scotland, Ireland, Sweden, Germany and Italy. These have been formed by the gradual accumulation of vegetable matter, reeds, roots of trees and the like; and some have required ages for their growth. There is an immense one at the mouth of the Mississippi river formed by the large quantity of trees, &c., floated down the river. In 1816 it was no less than ten miles in length, and 250 yards wide.
Lakes differ much in their clearness, color and depth. In lake Superior, fish, and the rocks are distinctly visible to an enormous depth. Some of the small Welsh lakes are perfectly black.
There are many other instructive and interesting peculiarities connected with lakes, but here we must stop; and in our next chapter, if the Lord will, we shall take up some of the wonders of the mighty ocean itself.