THE TELEGRAPH. 
182 
depth suffices. In the Atlantic, the cable was hooked with a 
line only one-fifth longer than the depth. 
Two kinds of buoys are used. The barrel or double-cone 
buoys (fig. 119) serve to mark the ends of a parted cable. 
They are fastened to a mushroom-shaped anchor (fig. 120). 
This anchor is itself attached to the cable by a chain, and a 
Fig. 121 . 
chain is also used in shallow water for attaching the buoys, 
but in deep seas lines are employed. 
Buoys provided with a staff and a flag that may be seen at 
a distance mark the position of the end, and are floated near 
the barrel buoys. They are used also to mark any particular 
spot with precision. 
When a cable has to be repaired, the first operation consists 
in finding by electrical tests the exact position of the rupture 
or fault. This delicate operation will be described further on. 
The distance and position of the fault having been found, the 
ship proceeds thither, the position being known by means of 
horizontal angles if the coast be in view, or if it be out of 
sight, by following a course determined by the log. In mid¬ 
ocean recourse must be had to the usual nautical observations, 
executed with the greatest possible accuracy. When the ship 
has reached the presumed locality, a flag buoy is fixed as the 
starting-point for further operation. The ship then throws 
out the grappling-iron and proceeds to drag for the cable, 
keeping, however, so far from the fault that if the cable be once 
