40 
THE TELEGRAPH. 
where however it is supposed that only ten correspondents 
belong to the group, whereas in reality there are twenty or 
thirty. The upper part of the commutator is a box containing 
as many Ader signals as there are lines, and marked by the 
proper numbers. The circles in the figure are the little 
windows at which the call-disc makes its appearance. Above 
is the electric bell, which can at will be connected with the 
signal detent, and made to establish a short circuit with a 
local battery. This is, when required, effected by means of the 
commutator I. But now r we suppose the clerk to be present, 
and to see the signal made by subscriber No. 5. Then he 
uses the lower part of the system, namely the Swiss commu¬ 
tator. It will be seen that each subscriber is there repre¬ 
sented by a band of metal bearing his number. Behind the 
wooden strip that supports these vertical bands at the front, 
are other horizontal bands (shaded lightly in the figure), 
crossing the former without touching them. But. it is only 
necessary to insert a metallic peg in one of the holes in the 
front bands, to connect it with one of the hinder bands. Each 
band is provided w T ith a peg. At present they are all at 
the bottom of the frame in the band marked terre (earth). The 
clerk takes out the peg in No. 5, and raising it a stage 
thrusts it in at the level marked tel (telephone). He is then 
in communication with No. 5, and taking his own instrument 
which is seen on the right, he asks, “To which number, sir, 
do you wish to speak ? ” “ To No. 9,” replies the subscriber. 
“All right, sir, I will inform him.” When the clerk has 
removed No. 5’s signal, he then shifts the peg of the band 9 
from terre to tel , precisely as for No. 5. The clerk is then in 
communication with the second subscriber, and calls by sounding 
his signal. 
If No. 9 be not too far from his telephone, this call will 
suffice ; otherwise, if there be much noise on his premises, he 
must be supplied with an Ader signal, provided with a bell 
apparatus. But in nearly all cases the telephonic signal is 
sufficient By one means or the other, notice is given to the 
subscriber No. 9, who answers, “Who calls me ? ” The clerk 
replies, “ No. 5 asks for you ; I am placing you in communica¬ 
tion with him.” Then, going back to No. 5, he says to him, 
“No. 9 has replied; you are in communication.” Then, 
