MAKING AND LAYING SUBMARINE CABLES . 165 
shocks that might be produced by sudden variations of the 
strain on the cable, are avoided. 
As, however, it is necessary in certain cases to relieve the 
table from a part or the whole of the strain induced by the 
regulating brake, the end of the lever, a, is connected with 
a chain passing over a drum to which is diametrically fastened 
another chain that passes over a pulley, and ends at a wheel 
fixed on the dynamometer. In this w^ay the effect of the 
brake may be regulated at will, according to the indication 
of the dynamometer, without any necessity for altering the 
weight p (see fig. 104). 
The dynamometer for measuring the tension to which the 
cable is subjected, is arranged as follows-:—In front of the 
drum of the brake, the cable passes over a grooved pulley, 
fixed at about 12 yards from the stern pulley, whence the cable 
falls into the water. Half-way between these pulleys, the cable 
passes under a third pulley supporting a weight, working up 
and down between rollers in a vertical frame with graduated 
uprights. As the strain upon the cable becomes greater or 
