278 
THE TELEGRAPH\ 
given the whole district in which the fire has broken out also 
receives the signal instantly and immediately. In a few 
seconds afterwards, orders are received from the central 
station, and thus unity of action is secured. 
The value of this system is proved by the fact of nearly 
one hundred cities in the United States and in Canada having 
adopted it, and maintained it continuously in action. Accord¬ 
ing to Mr. Saxton, the superintendent of the fire telegraphs at 
St. Louis, this system saves the fire assurance companies 
549,000 dollars a year. 
M. Truenfeld states that towns unprovided with fire tele¬ 
graphs are liable to a larger proportion of serious fires, on 
account of the greater delay in the arrival of the firemen on the 
scene. On the other hand, the more perfectly the system of 
fire telegraphs is developed, the smaller is the proportion of 
serious fires. 
Application of telegraphy to military operations .—According 
to M. Floridor Dumas, the first time a field telegraph was 
used in the French army was about 1857, w T hen the great 
Kabylie was taken. Marshal Eandon then ordered M. Lair, 
the head of the civil telegraphic service in Algiers, to follow 
up the head-quarters of the army with a wire attached to the 
trees. These orders were carried out, and it was from 
Souk-el-Arba, that, on the 24th May, 1857, the Marshal 
informed Algiers of the conquest of the first branches of the 
Djurjura. 
When the possibility of following the head-quarters of an 
army in the field by movable telegraphs was thus established, 
the plan first adopted was to place the apparatus in a light 
waggon, and to load a second waggon with the materials 
required in the formation of the line itself. Cables being 
often used, the same vehicle was sometimes made to carry 
the intruments and the reel from which the cable was un¬ 
wound. 
These “ carriage-stations ” made it possible to communicate 
between the ends of the line even during the march. The 
carriages were divided into two compartments, one of which 
serving as an office, contained the instruments, while the 
second held the reels of cable. The office had a table on 
which the instruments were placed, and a box containing the 
