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 proportions. Thus a very competent authority, Mr Cornelius Walford, gives it as his opinion that great fires, properly so called, "involving the loss of £50,000. and upwards, probably do not account for more than one-fifth of the losses of any average year." 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 attention of authorities. No means at present exist for accurately 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 imperfect 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 means 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 prevention; 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 0.95, stoves 1.67, other known causes 19.40, unknown causes 32.88. 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 inflammable 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 carefully 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 extinction of a fire in its incipient stages the water-buckets, handpumps, 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 has 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 where 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 firehose 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 following 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 factories, 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 compressibility affords the power which projects the liquid. The working pressure varies from 70 to 120 lb per square inch, according 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 g-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 fire brigade are worked most effectively by 26 to 30 men; pumps 6 or 7 inches diameter and 8 inches stroke. Each stroke (with 6-inch pumps) delivers 1 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 b. Fig. 2 represents the kind that is most in use in the United States. The diameter of the cylinder in this engine is 7 inches, and that of the pumps 44 inches, with a stroke of 8 inches.

14b sulphuric acid. The soda is dissolved in the water, and the acid is held in a leaden jar within the tank, which is securely closed. At the moment of using the sulphuric acid is mixed with the water, and instantly combining with the soda causes carbonic acid to be given off with a pressure

FIG. 3.-Chemical Engine.

of 140 b on the square inch. The tanks are used independently and charged separately, so that a continuous stream of water, usually inch jet, may be maintained. 300 feet of -inch rubber hose is carried. The whole apparatus, charged and carrying three men, weighs about

5000 b, and is drawn by two horses. The hose is rarely carried upon the engine; it is usually on a separate carriage drawn by one horse. The reel carries about 1000 feet of 3-inch rubber hose. Six hosemen ride on the carriage. The total load is about 3000 b.1

Ladder Carriages carry from 20 to 25 ladders of various lengths (see fig. 4). Two ladders spliced reach 70 feet. The carriage fully equipped and carrying. 12 men weighs from 7000 to 8000 b, and is drawn by two horses. The "aerial ladder" (so-called) reaches when fully extended a height of 100 feet, and is self-supporting; it is readily moved, when raised. It is made in 8 sections, each being a ladder about 12 feet long, and is put together and raised in six minutes. It is available as a fire-escape. The total load with its carriage is about 6000 Ib.

Electric Fire-Alarm Telegraph.-Time is a most important element in all fires, and the purpose of this telegraph is to put it in the power of any one discovering a fire to make known the locality of it to the fire department in the shortest possible time. Throughout the town or city "alarm boxes" are placed, connected by telegraph wire

1 A combined manual and chemical fire-engine is made by Dick of Glasgow, which consists of an iron tank on wheels, divided into two galvanized compartments. It has two pumps, with vertical motion, connected with the suction pipes, to fill the compartments with water where the chemicals are dissolved, and two pumps to project the chemical liquid from each compartment into the air-chamber, where they combine and generate carbonic acid gas. The gas is held in solution by the water, and is conveyed direct to the fire, upon which it exercises its fire-extinguishing power. The engine can be worked by minute, containing 250 gallons of carbonic acid gas, a distance of 75 four or five men, and is capable of throwing 30 gallons of water per to 90 feet.

engine-house, of the existence of a fire, by the action of the fire itself, and records there the number of the building and the room in which it occurs. The apparatus is very simple, and may be fully relied on. It consists of a small tube, called a thermostat, about 3 inches long, containing a spiral strip of metal, so arranged that the expansion due to a rise of thirty degrees above the ordinary temperature of the room in which it is placed, will close the connexion between the two poles of a battery, and produce an electric current, which, passing through a small iron box containing a clockwork and circuit breaker, called a "transmitter," at once strikes a bell and starts a register at the nearest station of the fire department, which records the number of the building and the room in which the fire has broken out. The thermostat is placed upon the ceiling of each room at intervals of 25 feet throughout the building, the transmitter in every room that requires a separate signal. The signal is transmitted even when the wires are broken. This telegraph has been adopted in New York and Boston.

The electric arrangements connected with the fire brigade in the city of Glasgow, which have been devised by Mr R. S. Symington, telegraph engineer, have been carried out on a scale of much efficiency and perfection. The city is divided into six fire districts, all connected by telegraph with the central principal station. There are also placed throughout the city 80 "electric fire alarm boxes," at the corners of the principal streets, and the occurrence of fire can through these be instantly telegraphed to the nearest "fire station," and at the same time to the "central station." On the arrival of the first detachment, the "box" from which the signal was given is by an ingenious arrangement immediately converted into a "telegraph station" (for the time being), connecting all the stations, and enabling the firemaster to command the whole "staff." The firemaster, as also the principal men, reside on the premises at the central station; and men and horses are summoned by an electric bell system leading into each man's bedroom. Besides the above arrangements there are placed in many warehouses and extensive establishments throughout the city about 2000 electric thermostats, by which the rising of a mercurial column causes a loud gong to sound, at once drawing attention to unoccupied or shut-up premises.

ORGANIZATION.-The organizations of Paris and Berlin are similar, and are based upon the idea of small tachments of men, lighter machines, and a large number of stations, and on the presumption that no fire will have got beyond the control of the small detachment before it is discovered and made known. The results have been generally satisfactory under the conditions existing in those cities. In London larger detachments and fewer stations have given

good results. In the principal cities of the United States different conditions have necessitated a proportionately larger force of men and more effective appliances. London. The metropolitan fire brigade is a force of about 400 men under the control of the Board of Works, but under the immediate command of the "chief officer." The city is divided into a number of districts, each under a "superintendent." Within each district are fire-engine stations properly equipped, each under an engineer." The force at these stations is the unit of organization. Each engineer has independent telegraphic communication with his superintendent, and he in turn with the chief officer. 26 steam fire-engines and 86 hand-worked engines are in use. Floating steam fire-engines protect the river front. The chief officer has absolute command at fires.

66

Paris.-The firemen are a corps, sapeurs-pompiers," attached to the War Department, but at fires the corps acts under orders from the prefect of police. It is under the immediate command of a colonel, and is divided into 12 companies, the company being the unit of organization. Fire stations, manned by three men and provided with handpumps and fire-escapes, are distributed throughout the city. If the three men of a station, with bystanders impressed into the service by the police, are unable to extinguish the fire, men from other stations of the same company are summoned. Additional companies are called out by orders from headquarters of the corps. Hand-engines are the main reliance, but in 1876 five steam fire-engines were in use.

Berlin.-The department is subject to military discipline, and is under the command of a "fire-director" with subor dinate officers. The city is divided into four inspection districts, with an officer in charge of each. Each district has numerous fire depôts, according to its needs, and each depôt is in charge of a fireman and four men, and is furnished with a small hand-engine, a hook and ladder, and a fire-escape. The principal stations are connected by telegraph.

New York.-The fire department of New York may be taken as the type of the best system now employed in the United States. It is on.a military basis, under the control of a board of commissioners appointed by the mayor. The active force is under the immediate command of the "chief of department," and consists of 10 battalions, each of 6 companies, in all about 750 men. Each company, whether engine or ladder company, has its own house, where the men live and the apparatus is kept. The whole force is at all times on duty and in the houses, except such small detachments as are on street patrol or at their meals. The horses stand harnessed in their stalls, which are placed immediately in the rear of the engine, and are loosened by a

simple mechanical appliance which, simultaneously with the striking of the alarm, opens the front of the stall; the horses, trained to move at the sound of the gong, advance rapidly each to his own place at the pole. They are instantly hitched in, the men spring to their seats, and the carriage is driven at high speed to the "alarm box" from which the alarm was given. To make sure that there will be a working pressure of steam on reaching the fire, the water in the engines, as they stand in the houses, is kept always at boiling point by the circulation of hot water from small stationary boilers, and fire is lighted in the engine the instant it leaves the house. Every effort is made to save even a few seconds of time, so that the interval between sounding the alarm and pumping water on the fire will average three minutes, and rarely exceeds five minutes. The city is divided into 10 battalion districts. The smallest of these represent each an area of about 5000 by 2000 feet, and comprise the most exposed parts of the city; but most of the districts are from two to three times as large. The signal boxes of the electric fire-alarm telegraph are placed conspicuously in the streets about 400 feet apart in the more crowded portion of the city, and from 1000 to 1200 feet in other portions. There are 540 in all. Alarms given from these boxes are instantly telegraphed from the headquarters of the department to each company house in the city. The first alarm calls out two or more companies previously designated; a second and third call out additional force. There are in use 57 steam fire-engines (5 of which are self-propellers), 1 steam fireboat, 10 chemical engines, and 18 ladder carriages, including 5 aerial ladders." The men are well-disciplined and skilful firemen.1

(A. P. R.)

FIRE-CLAY, FIRE-BRICKS. Fire-clays may be defined as native combinations of hydrated silicates of alumina, mechanically associated with silica and alumina in various states of subdivision, and sufficiently free from silicates of the alkalies and from iron and lime to resist vitrification at high temperatures; the absence of the vitrifiable element is, however, merely a question of degree, as no native clays are wholly free from iron, the alkalies, lime, and the other alkaline earths.

Fire-clay may be looked upon as a special term for the grey clays of the Coal-Measures, interstratified with, and generally in close proximity to, the seams of coal, in beds varying from a few inches to many yards in thickness. They are locally known as "clunches" and "underclays," and are supposed to represent the soil that produced the vegetation from which the coal was formed.

The association of coal with the fire-clays of the carboniferous formation has localized the manufacture of firebricks, and by far the larger proportion are produced in the Coal-Measure districts, especially at Stourbridge, celebrated for producing a highly refractory brick, Broseley, Benthall, Madeley and Coalbrookdale in the Shropshire coal-field, and in the Midland, Yorkshire, North and South Wales, Durham, and the Scotch coal-fields; but in later years the area of fire-brick manufacture has much widened. There has been an extensive production since about 1850 from the Eocene clays in the neighbourhood of Poole and Wareham in Dorsetshire; and a more limited supply from the Miocene between Bovey Tracey and Newton Abbot in Devonshire. 'Still more recently Cornwall has become the seat of the manufacture, where, as at Calstock, Tregoning Hill near Breage, St Ednor near St Columb, and Lee Moor, fire-bricks of fine quality are made from china-clay refuse and disintegrated granite. Mr Argall of the Tregoning Hill Company states that the locality was one of the The foregoing article is reprinted by permission of Messrs Little, Brown, & Co, Boston, Mass., from Great Fires and Fire Extinction, by General Alfred P. Rockwell, Boston, 1878.

which are employed by founders, smelters, gas companies, &c. The price paid at the works is from 50s. to 55s. per 1000. The source of the materials is decomposed granite, of which Tregoning Hill consists.

The

The Hingston Down fire-clay deposit, near Calstock, supplying the Calstock fire-brick works, the Phoenix works, and the Tamar works in the same neighbourhood, consists of a range of decomposed granite with an average width of three-quarters of a mile, running east and west for 3 or 4 miles, extending to an ascertained depth of from 300 to 400 feet, and intersected by mineral lodes. Calstock Fire-Brick Company (limited), superintended by Mr C. B. Evate, commenced operations in the year 1870, and manufactured from the decomposed granite fire-bricks of a highly refractory character, which are delivered free on board at the port of Calstock at from 50s. to 60s. a thousand, weighing about 3 tons. Another source of firebrick material, scarcely yet developed, is the pockets or depressions occurring in the mountain limestone of North Wales, Derbyshire, and Ireland, containing white refractory clays and sands, the insoluble remnants from the local dissolution of the limestone, intermixed with the debris of the overlying millstone grit. These clays and sands when evenly mingled are sufficiently adhesive to be moulded, and their small contractility and highly refractory character render them pre-eminently suitable for fire-brick manufacture. Fire-brick works have already been established on the estate of Captain Cooke of Colomendy Hall, near Mold, and the refractory clays and sands are largely employed for lining furnaces, 3000 tons having been sold for this purpose alone in the year 1877.

The fire-clays of the Coal-Measures vary as regards their refractory character, not only in the different coal-fields, but the individual strata in close alternation often present sudden variations, refractory beds being interstratified with useless strata largely charged with disseminated carbonate of iron. The grey colour of the Coal-Measure clays is partially due to the presence of this mineral, which, whether disseminated through the mass or otherwise occurring in excess as concretionary nodules, is prejudicial to the clays as a material for fire-bricks. Carbonaceous matter is also present in variable proportions, colouring the clay from a slaty-black to a pale grey, but as this is eliminated in the earlier stages of the burning of the bricks, its presence in no way influences their refractory character.

The relative proportion of silica and alumina which some manufacturers have laid undue stress upon as indicating heat-resisting quality is of little moment, as both these constituents, whether occurring in combination as silicates of alumina, or as free alumina and silica, are essentially the refractory elements of all good fire-bricks, being unvitrifiable per se, excepting when associated with the alkalies, lime, or oxides of irou. The plastic character of refractory clays is also of limited influence on their suitability for fire-brick manufacture; extreme plasticity, which is generally accompanied by excessive contractility and vitrifiability, is prejudicial. As a rule few clays or

Mottled sandy clay, Lower Bagshot Beds, Wareham

Clay from Upper Plant Bed, Lower Bagshot Beds, Studland Bay, Dorset..

11 "

13

13

13

15

"

15

6 ""

The clays above enumerated are not exclusively used for fire-brick manufacture, but fairly indicate the general character of the Tertiary fire-brick clays, which, compared with the Coal-Measure fire-clays, are characterized by a preponderance of alumina, tenacity of texture, contractility in the kiln, and an absence of iron and the alkalies, &c., which tend to vitrification. Tenacity of texture in a fire-brick material is, however, a mechanical condition, which, cæteris paribus, assists vitrification, a coarse open body being more refractory than a close homogeneous brick of similar chemical composition. A well manufactured brick should be of a pale cream or clear buff colour, uniform throughout its mass, and burnt to the full extent of its contractility.

The chemical changes which take place in the burning consist, first, of the destruction of the disseminated carbonaceous matter, the dehydration of the silicates of alumina, destroying their plastic character, and the decomposition of the disseminated carbonate of protoxide of iron,