One misadventure befell the Otter Rock light-vessel, which is moored in an open position over the rock of that name near Islay, although it was not the fault of either the system or the designing engineers. There was a flaw in one of the shackles, and while the ship was sawing and tugging at her anchors during a heavy gale the flaw asserted itself, the shackle broke, and the lightship got away. She was recovered with some difficulty, after having drifted about twenty miles. She was found stove in, having embraced the rocks during her wayward journey, but otherwise was unharmed. She was towed into port, repaired, and then taken back to her station, where she was secured more firmly than ever, while her chains were closely inspected to make assurance doubly sure. No repetition of the accident has occurred since, and the Otter Rock lightship, tethered firmly to the rock, rides gales and calms, throwing her welcome rays and droning her musical warning the whole year round as steadily and efficiently as if she had a crew aboard. A similar lightship was built for the Trinity House authorities from the designs of their engineer, Sir Thomas Matthews, for service on the English coast. This boat, built of steel, measures 65 feet in length, by 18½ feet beam and 10½ feet depth, with the lantern carried at the point of an open steel pyramidal structure, rising sufficiently high above the boat’s deck amidships to bring the focal plane 26 feet above the level of the water, thereby giving it a visible range of some ten miles. The boat is provided with two holds, in which the gas reservoirs are placed, the total gas capacity being about 1,500 cubic feet--enough to keep the light burning for one hundred days. This light is of the revolving type, and the rotation of the apparatus is accomplished very ingeniously. Before the gas passes to the burner, it drives a tiny three-cylinder engine, the crank-shaft of which is connected to the revolving apparatus through gearing. The speed of the turntable is kept constant by the aid of a governor, and the apparatus works so smoothly and perfectly that there is not the slightest divergence from the rate at which the apparatus is set. As the gas emerges from the engine, it passes to the burner to be consumed. By means of a novel apparatus, should anything befall the little motor or the rotating mechanism, the light does not drop out of service. In that event the gas flows directly to the burner, the only difference being that a fixed instead of a revolving light is emitted. [Illustration: _By permission of Messrs. Edmondsons Ltd., Dublin._ THE “6-BAR” FLOATING AUTOMATIC WIGHAM LIGHT IN PORTSMOUTH HARBOUR. This beacon, burning crude petroleum, burns for thirty days on a single oil charge.]