Page:Encyclopædia Britannica, Ninth Edition, v. 9.djvu/245

 FIRE It is of importance, however, to bear in mind that the loss of property by great fires or conflagrations is really small in proportion to the loss by fires of moderate propor tions. Thus a very competent authority, Mr Cornelius Walford, gives it as his opinion that great fires, properly so called, &quot; involving the loss of 50,000 and upwards, pro bably do not account for more than one-fifth of the losses of any average year.&quot; With the gradual improvement of the organization for coping with fires, the disproportion of conflagrations year by year becomes greater, so that really small but oft-occurring fires are now, in all well-governed communities, the subject which demands the careful atten tion of authorities. No means at present exist for accur ately estimating the average annual loss of property by fire throughout the world, as in scarcely any country is an official record of fires and their results kept ; and the im perfect returns of insurance companies are of comparatively little significance. It is estimated that the value of the insured property destroyed by fire all over the world amounts to from thirty to forty millions of pounds sterling annually. (See INSURANCE.) In modern times great improvements have been made in the moans employed for the prevention and extinction of fires. Broad thoroughfares have taken the place of narrow crooked streets; incombustible materials, such as brick, stone (natural and artificial), and iron are used, not only for the exterior, but for the interior of important buildings as far as practicable ; the introduction into cities of an abundant supply of water is common ; the electric fire-alarm telegraph, powerful steam fire-engines, extension ladders, and fire-escapes are among the mechanical appliances now in daily use. The two essential elements of the problem, however, are the fire-resisting character of buildings, and the organizations of trained men who can make the modern appliances effective. The methods of organization and procedure differ in different countries. Fires are dealt with, first and chiefly, by way of preven tion; secondly, by prompt measures for extinction when they have begun ; and thirdly, by circumscription or limitation when the fire has obtained such a hold of any building or range that the salvation of the burning property is beyond hope. In concerting preventive measures, a knowledge of the principal causes of fires is of the utmost consequence ; and as bearing on the ordinary causes the following abstract of the results deduced from about 30,000 fires, which occurred in London during the thirty-three years 1833-65, possesses significance. The percentages of different causes were : Candles 11 07, children playing 1 59, curtains 9 71, flues 7 80, gas 7 65, lucifers 1*41, smoking tobacco 1 40, sparks of fire 4 47, spontaneous ignition 95, stoves l G7, other known causes 19 40, unknown causes 3 2 88. There is too much reason to suspect that a considerable proportion of fires attributed to no known cause are due to incendiarism ; and were an official investigation into the origin of fires instituted, it most probably would result in a great saving of property. Among preventive measures the fire-proof building of large erections occupies an important place. Much can be done structurally to prevent and to limit fires, although it is now conceded that the thorough fire-proofing of any building is almost impracticable. The erection itself may be fire proof, but no sooner is it stored with inflam mable goods or property than it ceases to be invulnerable. It is of the utmost importance to reduce the danger of fire to a minimum in many public structures, as for example, public record offices, banks, and great libraries and museums, and in such establishments generally the most complete precautions are observed. Open fire-places are discouraged, arched floors are provided, the use of exposed wood is, as far as possible, avoided, gas and other lights are most care fully arranged, and fire -buckets, hose, and other appliances are in readiness for any emergency, while the premises are constantly patrolled by watchmen. For the prompt extinc tion of a fire in its incipient stages the water-buckets, hand- pumps, and extincteurs alluded to below are of the utmost value. When such means fail or are wanting, the services of fire brigades and salvage corps, if brought into requisition without loss of time, generally result in a great saving of property ; but when a fire lias obtained complete mastery of a building, it is a recognized fact that the most powerful engines, even aided with unlimited supplies of water, are ineffectual, and the efforts of the firemen are directed to confining the conflagration within the limits over which it has secured a hold. To cut off neighbouring properties, the use of gunpowder and other means of breaking connexion are frequently required. Fire Extinction, In coping with fires, water is the great agent employed; and in towns whore the supply of water is abundant, and where especially there is a constant and high pressure in the mains, the task of the firemen is much simplified. In such cases it is frequently only necessary to attach the fire hose to the plugs, and the pressure in the main pipe is sufficient, without the aid of any engine, to throw the jet over the whole burning mass. But it is only rarely that towns are so favourably situated, and for the equipment of an ordinary fire brigade and fire establishment the follow ing among other appliances are required. Hand-Pump and Bucket. A small hand-pump which can be set into a bucket of water is the most effective means of distributing a small supply of water without waste. If judiciously used it will put out any fire in its earlier stages. The Portable Chemical Extinguisher (fig. 1), Dick s Patent Extincteur, &c., designed to answer the same purpose as the hand-pump and bucket, are now in extensive use in fac tories, warehouses, and public buildings. The vessel is a cylindrical tank, holding 7 gallons or upwards of water, and is carried on the back. Carbonic acid is generated at the moment of using within the vessel itself, and from its compres sibility affords the power which projects the liquid. The working pressure varies from 70 to 1 20 Ib per square inch, accord ing to the temperature of the surrounding atmosphere ; and the projectile range of FIG. 1. Portable the jet is from 40 to 50 feet. Extinguisher. Hand-worked Engines consist essentially of a pair of single-acting force-pumps mounted on wheels and worked by hand. They vary much in size, weight, and power, and are hauled by men or horses. Those most used in Paris are worked by eight men, and throw a |-inch jet to a height of 100 feet. Each pump is 5 inches in diameter, with 9|-inch stroke. A smaller engine that may be carried into buildings by four men is also used. Those of the London firo brigade are worked most effectively by 26 to 30 men ; pumps 6 or 7 inches diameter and 8 inches stroke. Each stroke (with G-inch pumps) delivers If gallons of water. Still larger engines have been used, requiring 40 to 50 men. In the United States these as well as smaller hand-worked engines have given place to steam fire-engines, with pumps of the same size, in all the larger towns. Steam Fire-Engines are essentially a pair of single-acting suction and force pumps driven by steam power. They^are hauled by two horses, or are self-propellers. They weigh, as drawn to fires, from 5000 to 8000 Ib. Fig. 2 repre sents the kind that is most in use in the United States. The diameter of the cylinder in this engine is 7 7 ]- inches, and that of the pumps 4i inches, with ft stroke of 8 inches.