d, fit a glass like a linen tester to a
small disc of wood or brass to fit the cylinder. If magnifying
glass cannot be had, use plain glass and fit them as follows:

Make two rings of brass wire to fit tightly into the cylinder,
trace a circle (inside diameter of cylinder) on a piece of
cardboard; place cardboard on glass and cut out glass with a glass
cutter; break off odd corners with notches on cutters and grind
the edge of the glass on an ordinary red brick using plenty of
water. Place one brass ring in cylinder, then the glass disc and
then the other ring.

For the stand fill a piece of copper piping with melted rosin or
lead. When hard bend the pipe around a piece of wood which has
been sawed to the shape of bend desired. Then melt out the rosin
or lead. Make an incision with a half-round file in the under side
of the tube for the wires to come through. Make the base of wood
as shown in Fig. 1. One half inch from the top bore a hole large
enough to admit the copper pipe and a larger hole up the center to
meet it for the wires to come down.

If it is desired to make the light very complete, make the base of
two pieces of brass tube--one being a sliding fit in the other and
with projecting pieces to prevent the cylinder from going too far.
The light may then be elevated or lowered as wished. On two
ordinary brass terminals twist or solder some flexible wire, but
before doing so fix a little bone washer on the screws of the
terminal so as to insulate it from the tube. When the wires have
been secured to the terminals cover the joint with a piece of very
thin india rubber tubing, such as is used for cycle valves. The
two wires may now be threaded down the copper tube into the base,
and pulled tight, the terminals firmly fixed into the tubes; if
too small, some glue will secure them. To get the cylinder into
its carriage, put one trunnion into the terminal as far as it will
go and this will allow room for the other trunnion to go in its
terminal.

** Electric Alarm that Rings a Bell and Turns on a Light [337]

The illustration shows an alarm clock connected up to ring an
electric bell, and at the same time turn on an electric light to
show the time. The parts indicated are as follows: A, key of alarm
clock; B, contact post, 4 in. long; C, shelf, 5-1/4 by 10 in.; D,
bracket; E, electric bulb (3-1/2 volts) ; S, brass strip, 4-1/2
in. long, 3/8 in. wide and 1/16 in. thick; T, switch; F, wire from
batteries to