Another peculiarity distinguishes the Skerryvore from the Bell Rock. The sandstone of the latter is wave-worn, and broken up into a thousand rugged inequalities: the action of the sea on the igneous formation of the Skerryvore has, on the contrary, communicated to it the appearance and polish of a mass of dark-coloured crystal. It is so compact and smooth that the foreman of the masons, when he landed on it, said it was like climbing up the neck of a bottle. Moreover, notwithstanding its durability, the gneiss of Skerryvore is excavated into caverns, which considerably limit the area adapted for building operations. One of these caverns, we are told, terminates in a narrow spherical chamber, with an upper opening; through which, from time to time, springs a bright, luminous shaft of water, 20 feet high, and white as snow, except when the sun wreathes it with a thousand rainbows. * * * * * Mr. Alan Stevenson commenced actual operations in 1838 by the erection of a provisional barrack on piles, at such a height as to be beyond the reach of all average tides. This was designed to shelter the men at night, saving them the voyage to and from the mainland; and also to accommodate them when their work was suspended by bad weather. The first erection was swept away in a great gale on the night of November 3; but happily the labours of the season were then ended, and there were no occupants. On this occasion the grindstone was deposited in a hole 36 feet deep; the iron anvil was transported 13 yards from the place where it had been left; the iron stanchions were bent and twisted like corkscrews; and, finally, a stone weighing half a hundred-weight, lying at the bottom of an excavation, was carried to the highest surface of the rock. * * * * * Conquering all feelings of discouragement, Mr. Stevenson, in the following year, renewed his operations. A second barrack was completed by the 3rd of September. It was built of timber, and consisted of three stories: the first was appropriated as a kitchen; the second divided into two cabins, one for the engineer and one for the master of the works; and the third belonged to the thirty workmen engaged in the erection of the lighthouse. A more remarkable habitation than this was never dwelt in by human beings. It was an oasis in a wide waste of waters—a rude asylum suspended between sea and sky. Perched forty feet above the wave-beaten crag, Mr. Stevenson, with a goodly company of thirty men, in this singular abode, spent many a weary day and night at those times when the sea prevented a descent to the rock; anxiously looking for supplies from the shore, and earnestly longing for a change of weather favourable to the recommencement of the works. For miles around nothing could be seen but white foaming breakers, and nothing heard but howling winds and lashing waves. * * * * *