This is how it looks from the outside; but the greater part of those who see the engines go to a fire have no idea of the inner working of the system. All they know is that when there is a fire the engines go and put it out. We shall therefore now proceed to shew, first, the means for communicating alarms of fire; and second, the means for extinguishing fires when discovered.
There are in Boston (Mass.), which we may take as an example of a well-protected city, about two hundred and thirty-five alarm-boxes, which are small iron boxes placed at street corners, on public buildings, and in any convenient and necessary locality. Each box is connected by two wires with the head office at the City Hall, and has its number painted in red, and a notice stating where the key is kept, which is generally the nearest house. The authorities usually confide the key to some person whose premises are open all night, such as the proprietor of an hotel, an apothecary, or a doctor. When the box is opened, nothing is seen but a small hook at the top, the interior being concealed by another iron lid. Under this second lid is a steel cylinder with pieces of ebony let into its circumference to correspond with the number of the box. This cylinder is connected with one of the telegraph wires; and a steel spring which presses against it, with the other. When the hook is pulled down a clock-work arrangement causes the cylinder to revolve four times; the steel spring consequently passes over the entire surface of the cylinder four times, and contact is broken at the points where the spring touches only the non-conducting ebony. For instance, if the circumference of the cylinder in box 125 could be unrolled, it would present an appearance something like this: I II IIIII. Let us now follow the wires to the top of the City Hall, where, night and day, sits an operator watching the recording instrument. Here in a small room are numerous electrical instruments of all sorts, gongs, switches, keys, levers, and wires. In an attic overhead are the batteries. As soon as a box is opened and ‘pulled’ a bell strikes, and a recording instrument in front turns out a slip of paper, on which is printed the box number; thus
— — — — — — — —
would mean box 125. It prints this four times—the number of revolutions made by the cylinder in the box—to avoid any error.
On the other side of the operator are three clock faces bearing numerals from one to nine, and a pointer. The one to the right is for the units, the middle one for the tens, the one to the left for the hundreds. Under them is a lever working horizontally. Immediately the operator receives the box number, he sets these pointers to correspond with it—namely, the left one he puts at 1, the middle at 2, the right one at 5—thus making 125—and then moves the lever underneath.
Now let us see what is the result of this manœuvring. Wires connect these machines with various church bells and gongs in all parts of the city, which ring out the alarm as the operator moves the lever. There are thirty-eight such bells in Boston. When there is a church bell in the neighbourhood, the fire department affixes an electrical hammer to it; if, however, there is no public bell in the right place, a large gong is erected. The machine at City Hall is automatic when once started, and causes the bells to sound the alarm three times as follows. For box 125 they would strike once; then a pause and strike twice; another pause and strike five times; then a much longer pause and repeat twice. For box 218 they strike 2—1—8, always sounding the number three times with intervals between. So quickly is all this managed that in half a minute after a person opens and ‘pulls’ a box he hears the bells begin to respond.
In case that the engines which go on the first alarm are not sufficiently numerous to extinguish the fire, a second alarm is given by the operator striking ten blows on the bells, which brings several more engines. If the fire is very serious, a third alarm brings still more engines with hose and ladder companies. This is given by striking twelve blows twice. If the conflagration is becoming very serious indeed, the entire fire department is summoned by striking twelve blows three times. This, of course, very rarely happens. Indeed so efficient are the men and apparatus, that even a second alarm is quite unusual. The second and third alarms are communicated to the City Hall operator by simply ‘pulling’ the same box a second and third time; or if the pulling apparatus should have been destroyed at an early stage of the fire, by transmitting a request by a Morse telegraph key, which is placed in every box for the use of the employés when out testing the circuits. Every one knows the number of the box situated near to his residence or place of business; so, if awakened by the bells in the night, he simply counts the box number, and if it is not near him, turns over and goes to sleep again reassured; whilst if it chance to be his number, he is at once ready to render any assistance.
The fire telegraph is also made use of by the city authorities for calling out the police or the military in case of a disturbance, and also for informing the parents who send their children to the public schools when there is to be no class, on account of bad weather or other reasons. Each of these circumstances has its special number. There is also a gong placed in every police station, which is struck directly from the boxes, and it frequently happens that the police have a flaming building barricaded by a rope, before the engines arrive.
Next, the means for extinguishing fires when discovered. In the city of Boston there are twenty-nine steam fire-engines in actual service, and seven held in reserve; eight chemical engines, throwing water impregnated with soda and sulphuric acid, which also serves as the motive-power; one steam self-propelling engine; one fire-boat to defend the water-front of the city; nearly forty hose carriages, about seventy thousand feet of hose, and twelve hook and ladder companies; besides other apparatus of various kinds, such as hand-engines, coal-wagons, sleighs for carrying the hose in winter, and several aërial ladders. The engines weigh from seven to nine thousand pounds, and cost about a thousand pounds each.
One of the most interesting features in the American fire-system is the extreme ingenuity that is exercised to insure the speedy arrival of the apparatus at a fire. As has been said, in less than a minute after the alarm-box has been pulled the bells are ringing out the alarm all over the city; and—incredible as it may seem—sometimes in ten seconds after the alarm is rung, the engines have left their stations with steam up and every one prepared for work! Perhaps the best way to give a general idea of how this wonderful celerity is attained is to describe the interior arrangements of an engine-house.