THE SMITHSONIAN INSTITUTION. 153 



man listens to the public alarm bells and gets from them the number 

 of the district ; he runs by the nearest signal box and listens a moment 

 to gather the station number from its littl^ signal bell, and he now 

 knows that the fire is at district three, station five. He directs his own 

 motions and his engine, from the start, to within, perhaps, one hundred 

 yards of the fire. 



No other system has ever attempted to locahze a fire more precisely 

 than by the district number ; and in some cities, hke New York, the 

 districts may be two miles long. 



In all previous systems there has been a delay, first in getting an 

 alarm from the fire to the bells, and, second, in finding the place of the 

 fire in the district after the alarm was given, and reaching it by the 

 shortest route. By the fire telegraph both district and station are pub- 

 hcly notified; the one by the alarm bells, the other by the signal boiKes. 



Let us now consider tor a moment the analogy between the munici- 

 pal organization thus described and the nervous organization of the in- 

 dividual. A coal of fire falls upon my hand; one of the nervous ex- 

 tremities, or papillae, the " signal box" of the part, sends instantW its 

 own special signal, by means of a nerve of sensation or signal wire to 

 the brain, where the existence and locality of the lesion is at once re- 

 cognized. An act of intelligence and volition ensues. The watchman 

 d'the central station, or brain, does his part. An impulse to motion is 

 sent out over the proper motor nerves, or alarm wires, and muscles are 

 called into play in a suitable manner to remove the cause of injury, just as 

 the electro-magnetic muscles and iron limbs in the bell towers are 

 thrown into suitable and related action to the original cause and place 

 of alarm. 



Tile telegraph, in its common form, communicating intelligence be- 

 tween distant places, performs the function of the sensitive nerves of the 

 human body. In the fire telegraph it is made to act for the first time 

 in its motor lunction, or to produce effects of power at a distance; and 

 this is also connected with the sensitive function, through a brain or 

 central station, which is the reservoir of electric or nervous power for 

 tie whole system. We have thus an " excito-motory" systen?, in 

 which the inteUigence and vohtionofthe operator at the central station 

 come in to connect sensitive and motor functions, as they would in the 

 case of the individual. 



The conditions of municipal organization absolutely compelled the 

 relation of circuits which has been described. The analogy with the 

 laws of individual life was not perceived until after the system was 

 evolved, and it came then as a confirmation of the correspondence of 

 tlie system to natural law, and of the necessity of the arrangement as 

 a means of order. 



I should not be precluded from saying in this place, what historic 

 truth at this time requires, that the development of the " motor lunc- 

 tion" of electricity, or of the means by which electro-magnetic power 

 can be exerted at a distance, is due to the early experiments of the 

 Secretar}^ of this Institution, Professor Henr}^ whose discoveries in 

 electro-magnetism and especially of the quantity and intensity ot the 

 magnet in 1830, laid the foundation for all subsequent forms of the 

 electro-magnetic telegraph, and made subsequent steps comparatively 



