226 
THE TELEGRAPH. 
through the condenser, whilst with our arrangement shown in 
fig. 160, only the received signals affect the condenser. This 
gives the best results, and experience has shown that in this 
way the cable and the condenser preserve nearly an equal ten¬ 
sion, and thus the transmissions are facilitated. 
Fig. 159. 
By turning the commutator to the left, the signals given by 
the transmitting key pass into the line after traversing the 
apparatus by which they are recorded. A properly adjusted 
shunt, s, allows only a very small part of the currents for the 
line to pass into the apparatus. 
Thus the apparatus has the advantage of registering the 
signals that are sent as well as these that are received. 
