Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

employed, but with little success, for as fast as the material is removed another lot takes its place. The latest scheme is to sink a huge tube, operated from the salvage steamer, right through the water and sand into the vessel, the sand sucker helping in the process of forcing the tube down. The tube is provided with an air-lock chamber at its lower end, and the idea is that when a space has been cleared inside the vessel the diver, who has already entered the tube from the top, shall leave the air-lock and explore the cleared area, this operation being repeated till the whole vessel, or that part of it which is sup- posed to contain the treasure, has been searched. DEPTH TO WHICH DAYLIGHT PENETRATES UNDER WATER. This varies with the locality. For instance, in some of the Scottish lochs the water is so dark that daylight is lost to the diver when but a few feet below the surface. On the other hand, off the Rock of Gibraltar and in most tropical waters, he can see perfectly clearly when thirty fathoms and more down. SUBMARINE PHOTOGRAPHY. Many experiments have been carried out in this connection with varying degrees of success. We have in our possession photographs taken at Plymouth at a depth of sixty feet. For work of this description the camera is enclosed in a watertight metal case, and a very long exposure is necessary Further trials, which are now proceeding, will doubtless result in considerable developments in (he art of photographing beneath the waves. OXYGEN BREATHING APPARATUS. (Fleuss, Davis and Hill's Patents.) 1 his apparatus enables a man to work with safety in the most poisonous atmospheres. The air in the breathing bag is automatically replenished with oxygen from steel cylinders carried on the wearer’s back, the carbonic acid of the exhaled breath being absorbed by caustic soda. Equipped with this apparatus, a man has accomplished over 350,000 foot lbs. of work in two hours. Coj>\right