THE SMITHSONIAN INSTITUTION. 151 



formally, and with specific plans, before the city government of Boston, 

 and urged their action as due to science and to the pubhc interest. 

 This city government, unhke many others, induced only by the state- 

 ment of scientific truth, voted ten thousand dollars to test a system 

 wholly untried, and without precedent in the world. The mechanism 

 and construction were placed in the hands of Moses G. Farmer, esq., 

 and in 1852 were brought by him into thorough and successful opera- 

 tion. The American fire-alarm telegraph, in its development as a 

 practical system of organization, tested now for nearly three years, 

 should thus always be ascribed to Mr. Farmer equally with myself". 



It has been stated that the conditions of the fire-alarm telegraph re- 

 quire that information should, in the first place, come in from any part 

 of the circumference or surface of a city to its centre, and that thence 

 an alarm should go out in a definite form to the public. The organiza- 

 tion of a city under the system is as follows : 



From the central station, at the city hall, go out wires over the 

 house-tops, visiting every part of the city, and returning again. These 

 are the signal circuits, by which the existence of a fire is signalized 

 from any part of the surface of the city to the centre. Strung on these 

 circuits, or connected with them, are numerous signal boxes, or signal- 

 izing points, of which there ma}- be one at the corner of every square. 

 These are cast-iron, cottage-shaped boxes, attached to the sides of" the 

 houses, communicating, by means of wires enclosed in a wrought-iron 

 gas-pipe, with the signal circuit overhead. On the door of each signal- 

 box the number of the fire district, and also the number of the box or 

 station itself, in its district, are marked, and the place in the neighbor- 

 hood where the key-holder may be found is also prominently notified. 

 On opening the door of the signal-box a crank is seen. When this is 

 turned it communicates to the centre the number of the fire district and 

 of the box, and nothing else. Repeated turns give a repetition of the 

 same signal. By this means any child or ignorant person who can 

 turn a coffee-mill can signalize an alarm from his own neighborhood 

 with unerring certainty. 



Connected with the signal circuits at the central office, where they 

 all converge, are a little alarm-bell and a register, which notifies and 

 records the alarm received from the signal-box. The galvanic bat- 

 tery which supplies all the signal circuits is also placed at the central 

 station. If a fire occurs near signal-box or station 5, in district 3, and 

 the crank of that box is turned, the watchman or operator at the cen- 

 tral station will immediately be notified by the little bell, and will read 

 at once on his register the telegraphic characters which signify district 

 3, station 5. The characters used in the fire telegraph are a group of 

 dots to indicate the district number — as three dots for district 3, and a 

 group of dots and lines to indicate, by arbitrary characters, the station 

 number. Thus a line and two dots may indicate station 5. These 

 alternate on the record, and are repeated as often as the crank is 

 turned. 



The register used at the central station is generally the Morse regis- 

 ter; which I recommend, in connexion with the system, as being most 

 in harmony with its principle of operation. 



We have traced the alarm of fire from a sio;nal-box into the central 



