I must here remark, that before this plan can be properly put in execution, the firemen must be regularly trained to the exercise. When the firemen here are practised with the fire-escape, the man ascending or descending has a strong belt round his middle, to which another chain is fastened, and held by a man stationed at the window for that purpose; if any accident, therefore, were to occur with the chain-ladder, the man cannot fall to the ground, but would be swung by the chain attached to the belt round his body. The men are also frequently practised in ascending and descending by single chains. The firemen here are very fond of the above exercise; the bagging each other seems to amuse them exceedingly.[I]
The last resort, in desperate cases, is to leap from the window. When this is to be attempted, mattresses, beds, straw, or other soft substances, should be collected under the window; a piece of carpet or other strong cloth should be held up by ten or twelve stout men. The person in the window may then leap, as nearly as possible, into the centre of the cloth, and if he has sufficient resolution to take a fair leap, he may escape with comparatively little injury.[J]
FIRE-ENGINES.
In the application of manual power to the working of fire-engines, the principal object is, to apply the greatest aggregate power to the lightest and smallest machine; that is, suppose two engines of the same size and weight, the one with space for 20 men to work throws 60 gallons per minute; and the other, with space for 30 men, throws 80 gallons in the same time; the latter will be the most useful engine, although each man is not able to do so much work as at the former.
The reciprocating motion is generally preferred to the rotary for fire-engines. Independent of its being the most advantageous movement, a greater number of men can be employed at an engine of the same size and weight; there is less liability to accident with people unacquainted with the work, and such as are quite ignorant of either mode of working, work more freely at the reciprocating than the rotary motion. To these reasons may be added, the greater simplicity of the machinery.
Various sizes of engines, of different degrees of strength and weight, have been tried, and it is found that a fire-engine with two cylinders of 7 inches diameter, and a stroke of 8 inches, can be made sufficiently strong at 17-1/2 cwt. If 4 cwt. be added for the hose and tools, it will be found quite as heavy as two fast horses can manage, for a distance under six miles, with five firemen and a driver.
Fig. 1. Fire-Engine used by the London Fire Brigade. Longitudinal section,—with the Levers turned up for travelling.
This size of engine has been adopted by the Board of Admiralty and the Board of Ordnance, and its use is becoming very general.