s a handle round his dial until the pointer in its circuit
comes to the desired number. An electrical impulse is thus sent along
the wire to the central station for every number over which the
pointer passes, and the corresponding pointer or contact-maker at the
central station is moved exactly in sympathy. When the correct number
is reached the subscriber is in connection with the person with whom
he desires to converse. If, however, the latter should be already
engaged, a return impulse causes the bell of the first subscriber to
ring. Of course the prime cost of installing such a system as this
will be greater than in the case of the simple hand-connected
telephones; but the two systems can be used conjointly, and the
immense convenience, especially to large firms, of being able to go
straight to the parties with whom they wish to communicate, will
induce many of them to adopt the automatic apparatus as soon as it has
been perfected.

Wireless telephony must come to the front in the near future, but at
first for only very special purposes. The prospect of the profits that
would be attendant on working up a business unhampered by the heavy
capital charges which weigh upon the owners of telephone wires must
stimulate inventive enterprise to a remarkable degree in this
particular line. The main difficulty, however, in the application of
the system to general purposes will lie in the need for an ingenious
but simple means for enabling one subscriber to call another.

For this purpose probably the synchronised clock system already
referred to will be found essential, each office or house being
furnished with a timekeeper of this type kept in constant agreement
with a central clock, and so arranged that only when the ethereal
electrical impulse is given at a certain fixed point in the minute,
will any particular subscriber's bell be rung. This may be effected
by some such arrangement as a revolving drum, perforated at a
different part of its periphery for each individual subscriber, and
capable of permitting the electrical contact which makes a magnet and
rings the bell only at the fraction of a moment when the subscriber's
slot passes the pointer.

This will mean, of course, that only at a certain almost
infinitesimally small space of time in the duration of each minute
will it be possible to call any particular subscriber, or rather to
release the mechanism which will set his bell ringing for perhaps a
minute at a tim