This necessary operation of the laundry, however, does not affect tungstate of soda; and all the dresses of a household could be rendered non-inflammable and largely incombustible by dipping them in a solution of this salt. The proportions would be about one pound of the tungstate to a couple of gallons of water. For starched goods, the best way to use the tungstate would be to add one part of it to three parts of the starch, and use the compound in the ordinary manner.
Various methods have been adopted for fire-proofing wood, the strong solution of silicate of soda being one of the best. Asbestos paint is also useful, if it does not peel off, a little trick to which it seems addicted. By another method, the wood is soaked for three hours in a mixture of alum, sulphate of zinc, potash, and manganic oxide, with water and a small quantity of sulphuric acid. But while the inflammability of wood may be removed, it is questionable if it can be rendered entirely incombustible. In short, the problem of absolutely preventing fires by rendering substances perfectly fireproof has yet to be solved, if, indeed, it is capable of solution.
But if fire cannot be entirely prevented, could not some method be devised of automatically quenching the flames directly they break forth?
Such a method would appear like the prerogative of the good genii of a fairy fable, and beyond the reach of ordinary mortals. But science and human ingenuity which tell so many true "fairy tales" have made some approach to this also. The device is known popularly as "sprinklers," and is contrived somewhat in this way:—
Lines of water-pipes are conducted along the ceilings of the building, and are connected with the water supply through a large tank on the roof. To these pipes, the sprinklers are attached at distances of about ten feet. They are, in some cases, jointed with a soft metal, which melts at a temperature of about 160 degrees; the valve then falls, and the water is sprayed forth into the apartment.
Other sprinklers are said to act by a thread, which, it is claimed, will burn when the heat reaches a certain temperature and release the water. The essential idea, therefore, is that the heat of the fire shall automatically set free the water to quench it. Such great importance is attached to the use of sprinklers by some insurance-offices, that they offer a large reduction of premiums to those employing them. Again, other sprinklers are not automatic, but require to be set in operation by hand.
Nevertheless, in spite of all these varied precautions, it is unfortunately a platitude to say that fires do occur; but the point to be noted is, that but for these efforts, they would probably be greater in number and more destructive in their results.
Even when the flames are raging in fury, much may be done by courageous and well-trained men to preserve goods from injury; and, indeed, much is done by a body of men whose work is perhaps too little known. They pluck goods, as it were, out of the very jaws of the fire, and often while the flames are burning above them. Would you like to know them, and see them at work?
Behold, then, the black helmets and the scarlet cars of the London Salvage Corps.