To fix the base on to the top of the clock, the works must be removed (quite an easy matter to accomplish) and holes bored for a couple of screws put through from the inside.  If the underside of the base is not quite correctly curved, take care not to force in the screws far enough to distort the barrel.  It is advisable to do the fitting of the parts of the release after the base has been fixed, and before the works are replaced.  The position of the hammer shaft can be gauged accurately enough from the slot in the case.

The tails of the terminals T1 T2 must be truncated sufficiently not to penetrate the base and make contact with the barrel, or a “short circuit” will be evident as soon as the battery is connected up.

[Illustration:  Fig. 40.—­Electric alarm releaser, as attached to separate wooden clock casing.]

If the bell, battery, and clock are in the same room, a single dry cell will give sufficient current; but if the circuit is a long one, or several bells have to be operated, two or more cells will be required.

An Alternative Arrangement.—­Should the reader prefer to have the clock quite free from the release—­and this is certainly convenient for winding and setting the alarm—­he should make a little wooden case for the clock to stand in, just wide enough to take the clock, and the back just as high as the top of the barrel.  The release is then attached to a little platform projecting from the back, care being taken that the lever is arranged in the correct position relatively to the hammer when the clock is pushed back as far as it will go (Fig. 40).

If a self-contained outfit is desired, make the case two-storied:  the upper division for the clock, the lower for the cell or cells.  The bell may be attached to the front.  A hinged fretwork front to the clock chamber, with an opening the size of the face; a door at the back of the cell chamber; and a general neat finish, staining and polishing, are refinements that some readers may like to undertake.

Setting the Alarm.—­A good many alarm clocks are not to be relied upon to act within a quarter of an hour or so of the time to which they are set.  But absolute accuracy of working may be obtained if the clock hands are first set to the desired hour, and the alarm dial hand revolved slowly till the alarm is released.  The hands are then set at the correct time, and the alarm fully wound.

XIII.  A MODEL ELECTRIC RAILWAY.

The rapid increase in the number of electrically worked railways, and the substitution of the electric for the steam locomotive on many lines, give legitimate cause for wondering whether, twenty or so years hence, the descendants of the “Rocket” will not have disappeared from all the railways of the world, excepting perhaps those of transcontinental character.

[Illustration:  Fig. 41.—­Electric Locomotive.]