** Grooved Pulley Made from Sheet Tin [412]

A grooved pulley which will run true and carry a round belt may be
made without the use of other tools than a compass and pair of
shears, with a drill or punch for making two rivet holes.

Layoff a circle on the tin, of the diameter desired for the bottom
of the groove. Then layoff a concentric circle of 1/4 in. greater
radius. Cut out along the lines of the large circle. On the line
of the small circle mark with a prick punch or nail a series of
slight dents, about 1/4 in. apart, all the way around. Now make
cuts from the line of the large circle to these dents, stopping
when the shears give the little "click" on entering the dent. Bend
the little tongues thus formed alternately to the right and left,
then by shaping them with some care you will have a good running
surface for the belt. It will not make any difference if there are
more tongues on one side than the other, or if they are not
equally spaced, within reason.

For the hub, solder or rivet a "handle" across the center hole and
drill a hole through it of the same size as the center hole. With
the help of solder a grooved pulley which will answer almost every
experimental purpose may be made, and it is remarkable with how
slight care a perfectly true wheel may be made in this manner.

The same principle might in some way be applied to gear-wheels,
for light and temporary use.
--Contributed by C. W. Nieman, New York City.

** An Emergency Glass Funnel [412]

[Illustration: Cutting a Funnel]

Secure a glass bottle having a small neck and tie a string
saturated in kerosene around the outside at A and B as shown in
the sketch. Light the string and allow it to burn until the glass
is heated, then plunge the bottle quickly into water. The top or
neck will then come off easily. The sharp edges are ground or
filed off smooth. This will make a good emergency funnel which
serves the purpose well for filling wide necked bottles.
--Contributed by Jos. W. Sorenson, Everett, Wash.

** An Electrical Walking Stick [413]

A cane that will produce an electric shock when shaking hands is
one supplied with the electrical apparatus shown in the sketch. An
ordinary cane, 1 in. in diameter at the top and having a metal
band A, is bored about 8 in. deep, to receive the battery B and
induction coil C. One of the electrical connections is through the
metal tip D to the earth, the other is through the

[Illustration: Bat