An ingenious method of raising sunken ships has recently been devised by M. Pierre Hurzy, says the "Electrical Review." The system depends upon the use of calcium carbide for setting free gas when brought in contact with water. At suitable points in the vessel cases of carbide are placed, which, when brought into contact with water, force out the latter, thus emptying floats after they have been attached to the ship. The success of the method depends upon obtaining an equal buoyancy at different parts of the vessel.
For this purpose cans of carbide are placed at the points which are to be emptied of water. They are fitted with explosive caps, which are set off simultaneously by an electric current. In this way the case is ruptured, water is admitted and the emptying of all compartments begins simultaneously. It is suggested also by the inventor that the method can be used to advantage in operating floating docks. After such a dock has been sunk and has taken in the vessel to be lifted, the water is expelled from the ballast chambers by means of the acetylene gas set free from the carbide.
Lampblack is a soot, usually prepared by igniting resin or pitch, leading the smoke and vapor through an oily tube, where the oily products condense and then into a series of chambers, in which the carbon is deposited, the purest carbon being found in the chamber furthest from the point of combustion.