HOLYHEAD has been rendered a tolerably safe asylum for shipping at a vast expenditure of money and great exertion of scientific men. It possesses few natural advantages for a packet station or floating dock, the convenience of its position with regard to Dublin excepted; and for this pure reason it must continue an important position, until some other on the Welsh coast, possessing superior claims, be discovered and adopted by the legislature. Amongst the auxiliaries which art has contributed to give interest to Holyhead, the most picturesque and not the least important is the lighthouse, erected upon the South Stack. This singular Pharos stands upon a rocky island, the surface of which is elevated one hundred and twenty feet above the sea. It is separated from the mainland by a deep chasm, across which a chain suspension foot-bridge is thrown, from the mural cliff on the land side to the island. The descent from the top of the cliff to the bridge is effected by many flights of steps, cut in the front of the rock. The transit of the bridge is rather a nervous ceremony, and the fine craggs of serpentine rock, which overhang the gulf, are unequalled in the mineral kingdom, for variety of pattern and brilliancy of colouring. Beneath the island is a dark cave, excavated by the waves which dash into the narrow chasm with the utmost violence, and used in the milder seasons as a boat-house. On the highest point of the islet stands the lighthouse, a lofty hollow shaft surmounted by a lantern placed at a height of about two hundred feet above the sea, and exhibiting a bright revolving light, which bears upon the Skerries light south-west, half west nearly, eight miles. The light is produced by Argand lamps placed in the foci of metallic reflectors ground to the parabolic form. The sea cliffs of Holyhead mountain, presented to the South Stack Island, are beautifully bold, precipitous, and finely tinted with a variety of colours. Here innumerable sea birds, trusting to the dizzy and dangerous position of their dwellings for protection against human invasion, build their nests. But the ingenuity of man is only to be equalled by his courage, an assertion very fully substantiated by the trade of nest hunting pursued along these dangerous cliffs.