The charge of acid is contained in a glass vessel, and this is so arranged that when the machine is wanted, a blow on the top with a mallet causes the chemicals to unite, and produce, when in operation, a stream of fluid which can be projected fifty feet against fire with certainty of success. The value of this machine is increased by the fact that a certain measure of incombustibility is communicated to burning bodies after they have been operated upon by the chemical solution. So many serious fires could be stopped in their commencement if proper means were at hand, that the importance of powerful machines in small compass, such as these, cannot be over-estimated; and their efficiency is proved by there being no less than 45,000 in use, and 6,000 fires having been extinguished by them. It is calculated by actual operations that one gallon of the chemical charge in an exterminator will do as much good as twenty-five gallons of water.
Passing to the highest type of mechanical methods now in use, we have to consider a more complete but wonderful machine, the steam fire-engine. Within the lifetime of a young man such an invention was unknown to the bulk of people, and had not come into general adoption; in its place were parish hand-engines, and a few kept up by the Fire Insurance Companies of London. There was no system under which the firemen worked, no one responsible if the engine was out of order, or any untoward accident happened; and until the great Tooley Street fire discovered the alarming possibility of another Fire of London, the public seemed well content to leave their protection from fire chiefly to chance. Some remarkable revelations concerning the state of fire-engines in these early days may be found in Mr. Young’s exhaustive work on ‘Fires and Fire Engines.’ He gives an instance in which a woman was found to be manager of two parish engines; her husband had been sexton and parish engineer; and when he died, the parish authorities, not knowing what to do with the widow, appointed her as engineer. A writer in the ‘Quarterly Review’ for December 1854 relates that Mrs. Smith might be seen at conflagrations hurrying about in her pattens directing the firemen of the engine.
The present extensive application of steam-power for working fire-engines has arisen from the manifest inability of hand-worked machines to arrest the progress of large fires; from the very beneficial results that are attained by the use of steam fire-engines even at small fires; and, lastly, from the great improvements that have been made in the portable steam-engine within the last twenty years.
The first steam fire-engine was constructed by Braithwaite, of London, in 1830 (before the formation of the London Fire Brigade), but the recognition of this valuable invention as a regular fire brigade appliance did not take place till twenty-two years later, when its public use was established in New York. In the same year (1852) the London Fire Brigade employed Messrs. Shand and Mason to apply steam power to one of their hand-worked floating fire-machines, and were so satisfied with the results that they immediately procured an entirely new self-propelling floating steam-engine, constructed upon designs supplied in competition by Messrs. Shand and Mason, after receiving the approval of the late Mr. Walker, engineer, of Great George Street. This is still the most powerful efficient steam floating fire-engine that has been constructed, and is in use for river-side work in London. In 1861 the same firm supplied the first land-engine (single horizontal) purchased by the London Fire Brigade, which is still in excellent order. Many others have been since built by them, and also by Messrs. Merryweather and Sons, these two firms being the best known fire-engine makers. Steam fire-engines comprise three classes; land, floating, and fixed. The appearance of the land-engine is now familiar to all the dwellers in our large towns, most of whom have seen it in its rapid progress to a fire, drawn by horses, and carrying its complement of firemen. Floating steam-engines are desirable in ports and docks, where warehouses and storehouses of goods are in immediate proximity to water. They are self-propelling, or are placed in a vessel to be moved about by steam tugs. Fixed steam fire-engines are placed in manufactories and other places where the steam boilers are already in use, the steam from which is available both day and night for working the engine. The use of these fixed engines is of course limited to the premises where they are situated, but these they protect efficiently by means of an arrangement of fixed cast-iron pipes, with outlets for attaching flexible hose; and being without the boiler, carriage, axles, springs, &c., of the land steam fire-engine, the cost is very much reduced.
Messrs. Shand and Mason’s engines (see engraving on page 127) are all direct-acting, the steam and water pistons being connected by rigid rods, without the intervention of any joints, so that the force communicated by the steam to the steam-piston is instantaneously transmitted to the water-piston without any shock or blow. A crank is used to fix the length of the stroke, and to obtain a rotary motion with which to work the slide valve by an ‘eccentric,’ as in the ordinary steam-engine: a small fly-wheel is used in their single vertical, but none is required in their double or treble cylinder, nor in the patent horizontal engines. A great advantage, in Messrs. Shand’s opinion, attending the use of a rotary motion for steam fire-engines is, that it can be put in motion by hand in the engine-house as often as is necessary to prevent any of the working parts getting fixed through being out of use. In engines having no rotary motion this cannot be done without getting up steam, and frequently at fires the pistons have been found immovable, causing much valuable time to be lost. An engine with rotary motion does its work in a smooth and even manner, with a minimum of attendance on the part of the man in charge, and without the shocks, jerks, and irregular movement frequently found in those constructed without it.
The engines made by Messrs. Merryweather are in outward appearance somewhat similar to those just mentioned, but differ in constructional detail; the rotary motion is altogether dispensed with; the power is transmitted direct; and the working parts are perhaps fewer. This firm adopts long strokes of piston, and large cubical contents of cylinders; there are no cranks or dead centres, and thus the engines are stated to do a full amount of work with lower steam pressure and at less speed. Being direct acting, without fly-wheels, they work at any required speed to the maximum; it is stated they can be started in any position, and never set fast.