From the peak of the Æggischhorn the Alpine traveller obtains a fine view of its river-like course, and he sees beneath him, on the right hand, and surrounded by sheltering mountains, an object of almost startling beauty. “Yonder,” says Tyndall,[6] “we see the naked side of the glacier, exposing glistening ice-cliffs sixty or seventy feet high. It would seem as if the Aletsch here were engaged in the vain attempt to thrust an arm through a lateral valley. It once did so; but the arm is now incessantly broken off close to the body of the glacier, a great space formerly covered by the ice being occupied by its water of liquefaction. In this way a lake of the loveliest blue is formed, which reaches quite to the base of the ice-cliffs, saps them, as the Arctic waves sap the Greenland glaciers, and receives from them the broken masses which it has undermined. As we look down upon the lake, small icebergs sail over the tranquil surface, each resembling a snowy swan accompanied by its shadow.” This lake is the Märjelen Sea of the Swiss. [Illustration: THE ALETSCH GLACIER, SWITZERLAND, FROM THE ÆGGISCHHORN, SHOWING ITS MORAINES.] [Illustration: THE MÄRJELEN SEA, SWITZERLAND.] Professor Tyndall goes on to describe a spectacle which he witnessed, and which, as we have seen, is of frequent occurrence in the Arctic Seas. A large and lonely iceberg was floating in the middle of the lake. Suddenly he heard a sound like that of a cataract, and on looking towards the iceberg could see the water teeming from its sides. Whence came the water? The berg had become top-heavy through the melting underneath; it was in the act of performing a somersault, and in rolling over carried with it a vast quantity of water, which rushed like a waterfall down its sides. And the iceberg, which, but a moment before, was snowy white, now exhibited the delicate blue colour characteristic of compact ice. It would soon, however, be rendered white again by the action of the sun. We may contrast this picture of the solitary iceberg in the centre of the dark-blue lake with one which Dr. Hayes describes in his picturesque voyage in the open Polar Sea. After passing Upernavik he saw a heavy line of icebergs lying across his course, and having no alternative, shot in among them. Some of them proved to be of immense size--upwards of two hundred feet in height, and a mile in length; others were not larger than the schooner which wound her way amongst them. Their forms were as various as their dimensions, from solid wall-sided masses of dead whiteness, with waterfalls tumbling from them, to an old weather-worn accumulation of Gothic spires, whose crystal peaks and sharp angles melted into the blue sky. They seemed to be endless and innumerable, and so close together that at a little distance they appeared to form upon the sea an unbroken canopy of ice.