The gas cylinders are charged from the supply-ship through flexible hoses, the gas being compressed to about 180 pounds per square inch. The light is of sufficient power and elevation to be seen from a distance of some twelve miles. The beacon gives not only a visual, but also an audible warning. On the deck of the boat a bell is mounted, this being rung not only by the motion of the ship, in the manner of a bell-buoy, but also by the gas on its passage from the tanks to the lantern, the bell being fitted with two clappers for this purpose. The gas in passing from the tank enters a receptacle having a flexible diaphragm, which, as it becomes filled with gas, is naturally pressed outwards. On this is mounted a central metal piece, which is connected to a rod and lever. As the diaphragm is forced outwards, it moves the rod and actuates the lever, which, when the diaphragm falls, return to their normal positions. Attached to this mechanical arrangement is the bell-clapper, which alternately is lifted and dropped upon the dome of the bell, thereby causing it to ring. After the gas has performed its duty in raising the clapper lever and rod, it passes to the lantern to be consumed. Thus, while the light gleams brightly and steadily, the bell rings with unerring regularity--about three times per minute--day and night for months on a single charge; both must continue in operation until the supply of gas is expended. The success of this interesting and novel lightship has been responsible for similar installations in other similarly wild and exposed positions where approach is uncertain and often impossible for weeks at a time. [Illustration: _Photo by permission of Messrs. Edmondsons Ltd., Dublin._ THE LANTERN USED IN THE WIGHAM AUTOMATIC PETROLEUM BEACON. The circular shallow reservoir contains the burning-oil, which feeds the wick as it moves towards the burner, and also acts as a deck on which the lantern is built. In this ingenious system the flame is not produced at the end of the wick as in the ordinary lamp, but from the flat side of the wick, which is moved continuously in a horizontal direction over a small roller. By this means a light of uniform intensity is obtained, as carbonization cannot occur.]