VARIOUS APPLICATIONS OF TELEGRAPHY , 279 
batteries served as a seat. A bell and commutators were 
placed in front, and the connections were made by binding 
screws and gutta-percha covered wires. At night the work was 
carried on by the aid of a lantern. In the other compartment, 
the axles of the reels were supported by iron bearings, four 
on each side. Canvas bags containing the tools, and baskets 
of supports were also carried here. When laying the line, 
these bags were hung at the workmen’s waists. 
The earth-wire is screwed to one of the springs of the 
vehicle, which is in metallic communication with the brass 
nave of the wheel, whence a metallic rod proceeds to the iron 
rim surrounding the wheel. The earth connection is therefore 
never interupted by the motion of the carriage. This con¬ 
nection is often found to be inadequate. 
The line-wire is attached to the ironwork that supports the 
reels, and through it communicates with the cable or wire, 
even during the process of paying out. The earth connection 
is very uncertain when the vehicle is in motion, and it is some¬ 
times requisite to improve it by wetting the wheels, or by 
thrusting into the ground a spike provided with a hollow 
through which water is poured out. 
The head-quarters carriage being required to frequently 
move from place to place, has the same mobility as the 
“ carriage-station,” but, as it has to contain no paying-out appa¬ 
ratus, there are no reels of cable, and it is therefore more 
roomy. One side is occupied by a long table on which the 
instruments are arranged, and the batteries are placed 
under the seat in front of it. 
Twelve miles is about the average rate of progress per day 
But as the “ carriage-stations ” carry only four-fifths that length 
of cable, other carriages have been made to bear a supply of 
cable and the poles on which the overhead wires are supported 
in some places. These same carriages also contain the various 
kinds of insulators, stretchers, &e., and the several tools and 
implements required for the work. The lamps of the car¬ 
riages are so arranged as to be available for night work. 
In very rough country recourse is had to mules with pack- 
saddles, and in this case the moveable telegraph-office is formed 
of a small square tent for the operator, with a three-legged 
table to carry the instruments. These and the batteries are 
