back to its old position by the spring F,
thus driving the wheel A forward one division. G is a back-stop click,
and H, I, fixed stops.

It seems doubtful whether in large towns a number of dials could be
electrically driven from a distance because of the large amount of power
that would have to be transmitted. But for large buildings, such as
hotels, they are excellent. One master-clock in the cellar will drive a
hundred or so placed over the building. The master-clock may itself be
driven by electricity, but it will require the services from time to
time of some one to correct the time. Even this labour may be avoided if
the master-clock is _synchronized_, and as synchronization requires but
a small expenditure of force, it can be done over large areas. Hence the
future of the clock seems to be a series of master-clocks, electrically
driven, and synchronized one with another, in various parts of a city,
from each of which a number of dials in the vicinity are driven.
Electrical synchronization was worked out by Louis Breguet and others,
and a successful system was perfected in England by J.A. Lund. The
leading principle of the best systems is at each hour to cause a pair of
fingers or some equivalent device to close upon the minute hand and put
it exactly to the hour. Other systems are designed to retard or to
accelerate the pendulum, but the former appears the more practical
method. There is probably a future before synchronization which will
enable the services of a clockmaker to be largely dispensed with and
relegate his work merely to keeping the instruments in repair.

_Miscellaneous Clocks._--Some small clocks are made to go for a year.
They have a heavy balance wheel of brass weighing about 2 1b and about
2-1/2 in. in diameter, suspended from a point above its centre by a fine
watch spring about 4 in. long. The crutch engages with the upper part of
the spring, and as the balance wheel swings the pallets are actuated.
The whole clock is but a large watch with a suspended balance wheel,
oscillating once in about 8 seconds. Unless the suspension spring be
compensated for temperature, such clocks gain very much in winter.

An ingenious method of driving a clock by water has been proposed. As
the pendulum oscillates to one side, an arm on it rises and at last
lightly touches a drop of water hanging from a very fine nozzle; this
drop is taken off and carried away by the arm, to be subsequently
removed by adhesion