Fire Extinguisher. Many attempts have been made to produce apparatus to extinguish fires by excluding atmospheric oxygen from the flame. Among the earliest machines of this kind was that known as Phillips's fire an-nihilator, which was made of several sheet-iron cylinders placed one within another. Water was contained between the two outer ones, which when heated generated steam and discharged it into an inner cylinder.Within the latter was the gas-generating mixture, a compound of charcoal, nitre, and gypsum. An apparatus for igniting it consisted of a bottle of chlorate of potash and sugar, upon which could be emptied another of sulphuric acid. A mixture of gases and steam was expelled from the top of the machine.-An apparatus for extinguishing fires was invented by MM. Carlier and Vignon of Paris, and patented by them in 1862, for which a patent was issued in the United States in 1869 and reissued in 1872. The principal advantage possessed by this machine consists in charging water with carbonic acid gas and projecting it into the fire by the force of its own pressure.

Such a machine, made by the Babcock manufacturing company of New York and Chicago, who own the American patent, is represented in figs. 1 and 2. A metallic cylinder, of sufficient strength to bear an internal pressure of over 250 lbs. per square inch, contains in its upper part a glass or leaden vessel capable of holding 8 or 10 oz. of sulphuric acid. It is suspended by two pivots placed upon opposite sides and below the centre of gravity, but retained in an upright position by means of the stopper, which is held in the mouth of the vessel by a rod which passes through the hermetically adjusted cover. About 7 gallons of water holding in solution 2 1/2 lbs. of bicarbonate of soda is placed in the large cylinder, and about 8 oz. of commercial acid is put in the glass or leaden vessel, and held in position by the stopper and the rod which passes through the cover. The latter is then clamped to its place, and if the stopper be removed the vessel will become inverted by its own weight and the acid precipitated into the solution of carbonate of soda.

This causes the liberation of a quantity of carbonic acid gas, which at the ordinary pressure would occupy nearly eight cubic feet, but which under the pressure produced by its own elasticity, in this case about 100 lbs. per square inch, remains dissolved by the water. If a hose be attached to the stopcock placed in the lower part of the cylinder, a stream of water holding carbonic acid gas in solution is forced out with great rapidity, carrying with it bubbles of gas which are suddenly liberated by the diminution of pressure. It has been found that when this stream is projected upon a tire it possesses extraordinary extinguishing powers. A pair of large extinguishers may be mounted upon a carriage drawn by horses. This, known as the Babcock self-acting lire engine, is shown in fig. 3. These cylinders are capable of holding about 75 gallons each, and of sustaining an internal pressure of 400 lbs. per square inch. Many are in use in the United States, and are found to render efficient service in extinguishing fires before they have spread to much extent, and even then they may be used with advantage as aids to the steam engine, or alone.