that will be
mentioned serves to throw the balance in favor of the automatic.

The ease with which the automatic system lends itself to inter-office
trunking makes feasible a greater subdivision of exchange districts into
office districts and particularly makes it economical, where such would
not be warranted in manual working. All this tends toward a reduction in
average length of subscribers' lines and it seems probable that this
possibility will be worked upon in the future, more than it has been in
the past, to effect a considerable saving in the cost of the wire plant,
which is the part of a telephone plant that shows least and costs most.

=Automatic vs. Manual.= Taking it all in all the question of automatic
versus manual may not and can not be disposed of by a consideration of
any single one of the alleged features of superiority or inferiority of
either. Each must be looked at as a practical way of giving telephone
service, and a decision can be reached only by a careful weighing of all
the factors which contribute to economy, reliability, and general
desirability from the standpoint of the public. Public sentiment must
neither be overlooked nor taken lightly, since, in the final analysis,
it is the public that must be satisfied.

=Methods of Operation.= In all of the automatic telephone systems that
have achieved any success whatever, the selection of the desired
subscriber's line by the calling subscriber is accomplished by means of
step-by-step mechanism at the central office, controlled by impulses
sent or caused to be sent by the acts of the subscriber.

_Strowger System._ In the so-called Strowger system, manufactured by the
Automatic Electric Company of Chicago, the subscriber, in calling,
manipulates a dial by which the central-office switching mechanism is
made to build up the connection he wants. The dial is moved as many
times as there are digits in the called subscriber's number and each
movement sends a series of impulses to the central office corresponding
in number respectively to the digits in the called subscriber's number.
During each pause, except the last one, between these series of
impulses, the central-office mechanism operates to shift the control of
the calling subscriber's line from one set of switching apparatus at the
central office to another.

In case a four-digit number is being selected first, the movement of
the dial by the calling subscriber will correspond to the thousand