s are made in
various widths to fit the sides at the places where they are
wanted. The number of shelves can be varied and to suit the size
of the dishes. Cup hooks are placed on top and bottom shelves. It
is hung on the wall the same as a picture from the molding.
--Contributed by F. B. Emig, Santa Clara, Cal.

[Illustration: Cup-and-Saucer Rack]

Reversing a Small Motor [105]

All that is necessary for reversing the motor is a pole-changing
switch. Connect the two middle posts of the switch with each other
and the two outside posts with each other. Then connect one of the
outside posts of the switch to one brush of the motor and one
middle post to the other brush.

Connect one bar of the switch to one end of the field coil and the
other bar to one pole of the battery, and connect the other pole
of the battery to the other field coil. To reverse the motor,
simply change the switch.

[Illustration: Reverse for a Small Motor]

Referring to the illustration, the letters indicate as follows:
FF, field of motor; BB, brushes of motor; AA, bars of
pole-changing switch; DD, center points of switch; CC, outside
points of switch.
--Contributed by Leonard E. Parker, Plymouth, Ind.

** To Drive Away Dogs [106]

The dogs in my neighborhood used to come around picking up scraps.
After I connected up my induction coil, as shown in the sketch, we
were not bothered with them. A indicates the ground; B, switch;
and C, a bait of meat, or a tempting bone.

[Illustration: Shocking-Machine]

--Contributed by Geo. W. Fry, 903 Vine St., San Jose, Cal.

** An Automatic Lock [106]

The illustration shows an automatic lock operated by electricity,
one cell being sufficient. When the circuit is broken a weight, A,
attached to the end of the armature B, tends to push the other end
of the armature into the screw eye or hook C, which is in the
door, thus locking the door.

To unlock the door, merely push the button E, The magnet then
draws the armature out of the screw eye and the door is unlocked.
The dotted line at D shows the position of the armature when the
circuit is complete and the door unlocked. The weight must be in
proportion to the strength of the magnet. If it is not, the door
will not

[Illustration: Automatic Electric Lock for Doors]

lock, or would remain locked. The button can be hidden, as it is
the key to the lock.
--Contributed by Claude B. Melchior, Hutchinson, Minn.

** Experiment with Two-F