48 
THE TELEGRAPH,\ 
clerk, who then sees the number 411 displayed. The clerk 
then puts himself into communication with Brown, beginning 
with the queer but convenient expression, “ Hallo ! hallo ! ” 
Brown asks the clerk to put him into communication with 
No. 131. If this number is disengaged at the time, the clerk, 
presses a stud after having connected the wire of No. 131 with 
that stud. Jones’s bell then rings, and Jones, hearing it, 
touches in his turn his bell-stud, which causes the little door 
corresponding with his number to drop at the central station. 
When a direct line of communication has been established 
between the two horizontal bars corresponding with the line- 
wires of Brown and Jones, the two may converse in secret if 
the clerk withdraws his telephone. Should a third subscriber, 
No. 42, who may be designated Robinson, wish to correspond 
with Jones while Jones and Brown are still conversing to¬ 
gether, the clerk is able to take part in the conversation of the 
two last-named, just as a servant would in announcing a 
visitor. 
The person called by the clerk may then answer immediately, 
or cause Robinson to be made aware of the time when he will 
be at his service. If there be no objection to the conversation 
being carried on between Brown, Jones, and Robinson, a 
simultaneous communication between the three may be estab¬ 
lished by directing the clerk accordingly. The arrangement is 
equivalent to the “ Come in ” of every-day life. 
Telephonic communications, carried on in the manner we 
have just described in each of the two systems, prove of very 
great utility. They annul distance and bring the correspon¬ 
dents into each other’s presence as it were, so that a con¬ 
versation can be carried on as if the interlocutors were in one 
room. 
Let us point out some very ingenious arrangements in the 
details. When the conversation between Brown and Jones 
is finished, each of them hangs his telephone on its hook, and 
touches his stud. The number of each thereupon again appears 
at the central station, and the clerk there is made aware of the 
termination of the conversation. He closes the little doors, 
removes the connection between Brown and Jones, and all is 
ready for a new call. 
In stations where there are 500 or GOO subscribers, the 
