THE ORIGIN OF THE FIRE ALARM
Historic Sketch of Telegraphy to the Present Day.
In a paper read by Adam Bosch, of Newark, Nr J., at the convention of the International Association of Municipal Electricians, held recently at New Haven, Conn., the author, after enlarging on the vital necessity of an up-to-date fire alarm system and adverting to the old system of watchmen on towers striking the alarms on bells in New York and elsewhere, contrasted the existing congestion of the streets of cities, with their closely built tenement houses and huge factories, filled with inflammables, with the older stale of things when the conditions were far otherwise, and big fires were not so common. Nowadays, he said, much more prompt action is required to prevent disastrous conflagrations, and. I think, it will go unchallenged, or should, when I say that even the best disciplined and equipped tire departments, with all their time saving devices, such as swinging harness, sliding-poles, heaters to keep the water in the boilers of the engines at all limes at a steaming temperature, the most powerful engines and the fleetest horses, could not prevent the destruction of our g reat modern cities by fire without that agency which reduces the time-factor between the discovery of a fire and the knowledge of its existence by the lire department to the lowest possible figure—the tire alarm telegraph. On June 3, 1845, Dr. Channing wrote a public letter calling attention to a highly important application of the electric magnetic telegraph namely, to give an instantaneous, universal and definite lire alarm. Ilis plan was as follows: A central office established in some public building, in which to locate battery with a Morse register and an alarm bell, a double overheat! wire to proceed thence to every enginehouse and lire hell, and return to complete its circuit to the place from whence it started. In every station, a Morse register, in connection with an alarm hell, was to he placed, also a key, by the simple depression of which the signal would he instantly conveved to every other station on the circuit. the re might be four or five or more; every alarm passing through the central office. * * * iv slight change of the arrangement at the alarm-bell stations, and increase of machinery, the hammers of the bells could all he so disposed so to strike mechanically from the central office. The operator, therefore, by depressing a single key at certain intervals, would he enabled to ring out an alarm defining the position of the lire simultaneously on every church hell in the city. * * * The next effort was made in 1847. hv F. O. J. Smith, at that time in charge of the Morse telegraph interests in the New England States. He consulted Moses G. Farmer as to striking a number of large bells simultaneously by means of electricity. Farmer agreed to produce an apnaratus to do this, and soon showed a model of his invention.the falling ball electro-mechanical escapement, which was substituted for the mechanical escapement on a church-clock-striking apparatus in common use at that time. Mr. Smith immediately submitted to Mayor Quincy, of Boston, a plan’ for establishing a fire alarm telegraph by connecting fifteen engtnehottses by telegraph, and equipping three large bells, with electro bell-striking machines. to operate simultaneously from some convenient point, with the result that two such machines were ordered for the citv after a satisfactory public trial. No further action was taken, and the subject was abondoned till 1851, when Dr. Channing once more communicated with the municipal authorities as to his system, with its proposed signal and alarm circuits, the division of the city into six districts, a description of the apparatus required and an estimate of the probable cost. He also offered to give an exhibition to demonstrate the feasibility of the system. The central office was to be at the cityhall ; the apparatus to consist of a relay on every signal circuit, and a local circuit to operate a register and alarm bell. To transmit alarms to the large bells, a Morse instrument, moved by clockwork, was suggested—namely, a wooden cylinder, with a metal core, over which were a number of keys, like those of a piano. Under each key strips of metal in groups were fastened to the cylinder and connected with the core. The cylinder being set in motion and one of the keys depressed, a spring would bear on the cylinder, and, if properly connected, a signal was given corresponding to the number and position of the metallic strips under this particular key. Dr. Channing found the two models of the machines made in 1845 stowed away in a lumber room. He decided to use the two models of the 1845 machines and Farmer promised to help him. The trial was successful and resulted in an appropriation of $10,000 by the city to carry out the proposed plans. Farmer was appointed superintendent of construction. * * * In the construction of the signal Ixixes the first departure from the original plan was made by adding a break-wheel to operate the key. A crank at first tried was discarded as too intricate. The signal keys, also, caused considerable trouble in their point of contact. A sliding contact was, therefore, substituted, and the improved apparatus gave the station number, the district numbers by dots and the station number by dashes and dot$. There was great difficulty over the construction of the bellstriking machines. Fanner’s original models had been made to strike bells weighing from 75 lbs. to 150 lbs., and now nineteen machines were to be built to strike bells weighing from 300 lbs. to 3.700 lbs. and all to strike successive blows in the same short period of time. Weights of from 800 ills, to 2.000 Ills. were, therefore, affixed. But much trouble was experienced, and the whole arrangement was experimental. * * * Locality and turret-space had to be considered, and the apparatus so modified that it might be properly placed. Every experiment, also, had to be made in public, and the constant clanging of the bells caused endless complaints. To economise battery power, three metal springs were placed on the underside of the keys. Each was connected wit] 1 one of three alarm circuits and. as the cylinder revolved, each metal strin on its surface made connection with each spring successively, thus allowing the same battery to be thrown on each of the three circuits in quick succession. To admit of the use of the Morse register in connection with the alarm circuits, an indicator was devised, with three revolving cylinders showing the numbers in large plain figures. There was, also, an automatic circuit-testing clock, which tested the circuits once every hour. In 1832, the system was deemed sufficiently reliable to submit it to public use. But the original $10,000 was spent before the work was completed, and nearly $6,000 more was necessary. Instead of twenty-six signal stations, thirty-nine were established. O11 April 28. 1852, the newsystem went into effect. There was considerable misgiving concerning its reliability, and it was not groundless. * * * On January 1, 1852. Farmer was elected superintendent of the system for six months. * * * He accepted the position; but three years passed before he considered the system in such a condition that he might safely place its management in other hands. The first city, after Boston, to adopt the fire alarm telegraph was Philadelphia, where it was introduced in 1855. I 1855 Dr Channing delivered a lecture on the system at the Smithsonian Institute, and through the lecture the attention of J. N. Gamewell was first directed to the fire alarm telegraph. He then acquired the rights for the Southern and Western States. The fundamental patent covering the invention of the fire alarm telegraph was granted to Channing and Farmer May 19, 1857. Another patent was issued to them on March 8, 1859, for a repeater. Mail}’ subsequent patents were granted to Farmer alone, among them one for an automatic svstem in which the central office is dispensed with, and the signal boxes and alarm bells are all placed on one circuit, so that, when an alarm is given, all the bells strike instantly and simultaneously, without the aid of an operator. This was the village system. * * * A very important improvement was made and patented in 1856 by Chas. G. Chester, namely, an “automatic electrical circuit-breaker.” The break-wheel was moved automatically by clock-work, actuated by a spring. It never came into public use, but it was practically the first automatic signal box known. After three years of hard work. Gamewell & Co. installed a plant in St. Louis in 1858—the third city to adopt the fire alarm telegraph. In 1859 Gamewell & Co. obtained, by purchase, complete control of all patents relating to the fire alarm telegraph granted to Channing and Farmer or to Farmer alone. To make the system absolutely perfect, Mr. Gamewell gathered round himself men of the highest inventive genius and mechanical skill. * * 1 lie first fire alarm system, equipped with automatic signal boxes, was introduced into Mobile, in 1866. Four circuits were provided. To make that possible, a new apparatus was invented, by means of which a signal from any one circuit was automatically transmitted to every other circuit. and mechanically closed the others, should anv one circuit remain open. This was patented in 1870 by Edwin Rogers, * * * The original crank signal boxes remained in Boston until 1866. when automatic boxes took their place. In 1867 Joseph B. Stearns, now’ superintendent at Boston, received a patent for an apparatus operated by “reverse currents,” which permitted the use of the same wire for receiving a signal from a box and transmitting it to the alarm bells. Several years before the introduction of automatic signal boxes, Stearns abandoned the method of striking the district numbers on the bells, and designed boxes to strike the box numbers only. * * * The adoption of the automatic signal-box caused the speed with which a fire alarm box was operated to depend no longer upon the condition of the person giving the signal. When an error was made, it w»as usually the first round that was found to be w’rong, because the person giving the alarm, after the first pull, would give the hook another pull or two. This suspended the movement of the break-wdieel, and, if it occurred between two successive breaks, a long pause followed, and the signal would either be unintelligible or a number entirely different from the number. Two patents to remedy this difficulty were issued in 1869 for “non-interference pulls.” one to Steven and Chas. G. Chester, and the other, to Edwin Rogers and Moses G. Crane. In the former invention, after the box was in operation, the hook could not again engage the mechanism until the full number of “rounds” was completed. In the latter, the mechanism could be engaged after each full round. * * * Then came tbe interference caused by pulling a box while an alarm from another box was in process of transmission. The first patent for a non-interference box w’as issued to J. N. Gamew’ell in 1871. His was the first normally wound box, not actuated by weight or spring. It had a trigger-pull. and a w’heel which, in its revolution, keeps the circuit open for the greatest length of time consistent with the proper transmission of the signal. It also contains an electric magnet, and an armature which, when it is in position awav from the magnet, shunts the break-wheel, it the armature is in its normal position against the magnet, it is held there by a simple contrivance until the signal is completed. If a box is pulled while another one is in operation, the same contrivance holds the armature in a position to shunt the break-wheel of the second box during the time of its operation. The only chance of an interference lies in the possibility that the hook of the second box is pulled the instant the circuit is closed, the armature being held close to the magnet. But. owing to the construction of the skeleton break-wheel these periods of contact are exceedingly brief, and the chances of an interference are very remote. 111 1880 J. M. Gardiner patented a non-interference signal box, which, because of its great simplicity and mechanical perfection, has maintained its great popularity to the present day. Its construction is too well known to need any description. The most effective remedy against the interference of signals is the Gamewcll patented system of interlaced circuits, in which the circuits are so run that no two adjacent boxes are on the same circuit. This best suits cities with a long, but narrow territory. In others, the great amount of wire required to carry out this principle fully bars its general adoption. With interlaced circuitalso, in case of an open circuit, no two adjacent boxes are out of service at the same time If two signal boxes of the non-interference type are milled nearly at once, the first pulled by as much as the fraction of a second will transmit itsignal, the other will not work. To prevent the loss of this signal. John J. Ruddick. in 1889. patented a signal box in which this was ingeniously accomplished. * * * As to the cells: tbe first unreliable Grove cell was ill adapted for a fire alarm telegraph where uniformity of current strength is essential. The Daniel cell, its successor, was trenerally employed up to 1871. when the Callaud. or gravity cell was introduced and in a short time every fire alarm telegraph was equipped with it. For over twenty years it was the only cell used for this service. Within the last ten years, however, it has been superseded in many places by tbe storage battery, with very satisfactory results. The automatic repeater of Edwin Rogers, was gradually improved in him. as well as bv J. N. Gamewell and Moses G. Crane, until it has become an apparatus of almost absolute reliability. The general plan of a modern central office fire alarm system still re~emiiles that nitlined by Dr. Channitig si xiv ears ago, bin, in the lnstrumeut~ and apparatus used. most voitiieiful improvements have been made. rite Morse register has been replaced i)y the multiple pen register, with automatic time at lip. The old keyboard, at an early period. gave ivav to a separate dial transnhitter with an index for ever~’ digit in the number to be transmuted. On receiving a signal, tile operator moves the iitdexe~ to the respective tiglires. and starts the clockwork. A method still in use in New York city. hasa duplicate break-wheel for ever signal iii x titi miter in the sv stem. The operator. on receiving a signal of fire, selects the corres 1)011(1mg wheel and inserts it on the wheel-sbatt of the transmitter. The most unproved modern traiisiiiittei in use in tile larger cities have three or four dials of cacti to he used either singly or in combination. This apparatus is manipu lated with great rapidity and precision. and, as only the iiuniiiers to which the dials arc set are exposed to i ew. the hahility to error on the part of the operator is reduced to a minimum.