Curious Causes of Fires.
The Railway Review has collected some curious examples of the way in which fires may be set. In one instance, where some waste, which had been used with mineral oil, had been thrown into a safe place, an insect crawled through it and then, carrying some pieces of the oily fiber sticking to his body, made his way to a gas jet. The cotton fibers which adhered to him caught fire, and he dropped, blazing to the floor, setting the building on fire. In another case, a quantity of waste was said to have been ignited by the friction of a belt running close to it. This, however, may be considered doubtful. The friction of a belt against soft cotton is by no means of a nature to produce great heat, and a much more rational explanation is to be found in the supposition that an electric spark passed from the belt to some conducting substance through the cotton, which it ignited on its way, asjsparks of frictional electricity can easily do. In fact, the electrical effects accompanying the running of large belts are quite important, and it is probable that more than one fire has been due to them. Sparks can be taken by the finger from almost any large belt in motion, and we have known a case where an ingenious engineer, by fixing a metal comb near the belt, succeeded in drawing off enough high tension electricity to enable him to light the gas jets in and about the engine room without matches by simply touching them, after turning on the gas, with a wire connected with the comb.
In two cases destructive fires have been caused by water. In one of these a flood caused the water to rise high enough in a factory to reach a pile of iron filings. The filings, on contact with the water, oxidized so rapidly that they became intensely heated, and then set fire to the neighboring woodwork and the building was destroyed. In the other case, the water from the engines, during a fire, found its way into a shed containing quicklime, and the heat generated by the slaking of the lime set fire to the shed, and this to other buildings. Quicklime fires, however, are not uncommon. Many vessels carrying quicklime have probably been burned by the admission of water to the lime through a trifling leak, and no architect or builder needs to be told how intense the heat of slaking lime may be. Glass globes, which act as lenses, often set fires, and it has recently been claimed, on high authority, that the convex glasses used in sidewalk lights are dangerous, and should be abandoned in favor of lights with flat tops. As the convex glasses receive and transmit much more light than the flat ones, particularly in muddy weather, it seems hard to be obliged to give them up, and perhaps a lens might be made convex on the outside and concave on the inside, the concavity being equal to or greater than the convexity, so that rays of sunlight would either pass through unchanged in direction or would be dispersed instead of being concentrated, so as to unite the advantages of the convex form with complete security.