A Life-line Air Cannon.

New Zealand Graphic, Volume XLIII, Issue 2, 14 July 1909, Page 43

A Life-line Air Cannon.

THE ordinary rocket as a means of establishing communication between a wrecked ship and the shore in stormy weather has the disadvantage of being severely limited in its range of action, and when discharged in the teeth of a gale the deviation in the line of flight still further reduces the range. The question of establishing a more efficient and longer range system has occupied the attention of the British Government for some time past, and a few months ago the department of the Board of Trade established a special committee of experts, for the purpose of examining and thoroughly testing various improved devices for throwing lifelines, as well as other contrivances for connecting a wreck with the shore, so that the ordinary breeches buoy may quickly be brought into service for succouring those in distress.

Among the various contrivances investigated was an air cannon, invented by Mr Alexander J. Macleod, of West Hartlepool. which attracted particular attention. The rough full-sized model used in these trials is shown in the accompanying illustration. It comprises a cannon mounted on a four-wheeled carriage for convenience of transport. Compressed air is used as the propelling agent for throwing the missile to which* the life-line is attached. The cannon is elevated through a wide angle by gearing, and mounted on either side is a crank wheel for use in compressing the air to provide the propelling charge. The two cylinders are mounted on the barrel of the gun and fitted with the usual prear

sure gauge, a special valve being used to control the admission of the charge into the breech when desired. The life line is coiled on a winch mounted in the front part of the carriage beneath the cannon, and fitted with special check action to prevent the line from paying out too rapidly while the projectile is in flight, and thus becoming tangled. The barrel of the cannon is sft in length, and the air-compressing mechanism is designed to supply sufficient energy to throw the*line a maximum distance of half a mile under its full compression charge. It is not necessary to use the full compression charge when effecting communication over a shorter intervening space, the gauge being graduated to fulfill various requirements as to Tange, while in heavy weather, where increased resistance to flight is encountered, a greater charge than that which is normally adequate for the distance can be used.'

This line-throwing apparatus, unlike the majority of such appliances, is particularly designed for attachment to ships. 'As is well known, vessels are for the most part unprovided with any linethrowing facilities, albeit that in the majority of instances the possibilities of establishing communication between the Wreck and the shore, from the ship itself Me greater than in the reverse direction.

since the land offers a better target for the alighting of the line-carrying missile than the vessel, and the fact that in the majority of wrecks the wind is invariably blowing strongly on shore, so that the very agency which retards the flight of the rocket fired from the beach tangibly assists that thrown from the ship. But the use of a rocket apparatus and similar agencies from a deck is attended with great risk, especially if the ship be carrying an explosive or inflammable cargo. With the Macleod apparatus, owing to compressed air being the propelling agent, the cannon ean be discharged in the closest proximity to any combustible cargo with absolute safety. <3> <S> Radium. As a result of a lecture delivered by Sir Frederick Treves, the eminent British surgeon, in which he illustrated some practical curative results attained by the use of radium, a British Radium Institute has been found for carrying out research operations in connection with the application of radium to surgery. In the course of his lecture, Sir Frederick Treves recorded the specific cases in which an absolute cure had been effected. He stated that radium can cure every form of naevus: will eradicate the terrible port-wine stain, which is probably one of the greatest disfigurements with which one ean be afflicted: and will rid the patient of the pigmented mole and hairy mole. A naevus the size of a gooseberry on the top of th< head was completely removed. In another case a girl suffering from a large angioma on her eyelid was rid of the malady by this means, when four surgical operations had failed. Possibly the most striking case was that of a young woman who had an angioma covering practically the whole of one side of the face. Repeated operations proved abortive, but under the radium treatment success was soon achieved. These •were all affections of the skin. To show that it is equally successful in other eases, a boy who had a fibrous angioma as large as a hen’s egg on one arm, had it completely dispersed in the course of four weeks. The successful disappearance of a solid mass of such size the surgeon described as marvellous. <e> <s> <s■ A Mammoth Bridge. The first official statement of plans for the great bridge across Hell Gate, New York, which will serve to connect the system of the New Haven Railroad Company with that of the Pennsylvania Railroad Company on Long Island, was recently given cut. The bridge, including its' steel approaches, will be about a mile and a-half in length, with a central span above Hell Gate 1000 ft in length, having 135 ft headway above the water. It will be a braced arched structure, the total height of the arch above the suspended roadway being 140 ft. The crown of the arch will be 277 ft above the water. The structure will provide four railroad tracks, capable of carrying the heaviest load of locomotives and freight trains upon all four tracks at tfce same time. This will be the heaviest span, per foot of its length, of any of the existing long-span bridges of the wnrld. Training the Tramway Men. The motormen and conductors of the Lake Shore Electric Railway Co.. Cleveland, U.S.A., are being subjected to a series of tests which are quite rigid. A special car has been fitted up, in which these tests take place. Not only are the motormen required to learn the operating rules of the company, but thny must be able to make any slight or temporary repairs to their motors. One side of the car is fitted with a dark room, where the men are subjected to a colour test. A novel feature of the test in this room is that which requires the men to judge distances by the sizes of illuminated signs. Different sized tail lights, letters, etc., are used, corresponding to the sizes as they would appear at different distances from the car, and the men are required to determine their distances merely from their size.