ue to set. A fiber washer is then put between the plates and a
brass tube axle placed through the hole. The plates, turned wood
pieces, and brass axle turn on a stationary axle, D.

The drive wheels, EE, are made from 7/8-in. material 7 in. in
diameter, and are fastened on a round axle cut from a broom
handle. This wood axle is centrally bored to admit a metal rod
tightly, and extends through the standards with a crank attached
to one end.

Two solid glass rods, GG, Fig. 4, 1 in. in diameter and 15 in.
long, are fitted in holes bored into the end pieces of the frame.
Two pieces of 1-in. brass tubing and the discharging rods, RR, are
soldered into two hollow brass balls 2 or 2-1/2 in. in diameter.
The shanks of the collectors are fitted in these brass balls with
the ends extending, to which insulating handles are attached.
Brass balls are soldered to the upper ends of the discharging
rods, one having a 2-in. ball and the other one 3/4 in. in
diameter.

Caps made from brass are fitted tightly on the ends of the
stationary shaft, D, and drilled through their diameter to admit
heavy copper rods, KK, which are bent as shown. Tinsel or fine
wire such as contained in flexible electric wire are soldered to
the ends of these rods, and the brushes thus made must be adjusted
so they will just touch the plates. The caps are fitted with
screws for adjusting the brushes. These rods and brushes are
called the neutralizers. A little experimenting will enable one to
properly locate the position of the neutralizers for best results.
--Contributed by C. Lloyd Enos, Colorado City, Colo.

** A Concrete Swimming Pool [178]

[Illustration: Home-Made Swimming Pool]

Several boys from a neighborhood in the suburbs of a large city
concluded to make for themselves a swimming tank of concrete. The
money was raised by various means to purchase the cement, and the
work was done by themselves. The ground was selected in a secluded
spot in a neighbor's back yard and a hole dug to a depth of 4 ft.,
12 ft. wide and 22 ft. long. The concrete was made by mixing 1
part cement, 4 parts sand and 10 parts gravel together and the
bulk moistened with water. The bottom was made the same as laying
a sidewalk, and forms were only used for the inside of the
surrounding wall. The tank may be hidden with shrubbery or vines
planted to grow over a poultry wire fence.

** Old-Time Magic-Part IV [179]

Cutting a Thread Inside of a Glass Bottle [179]