h merriment.
Unless the trick is thoroughly understood, for some it will turn
one way, for others the opposite way, while for others it will not
revolve at all. One person whom I now recall became red in the
face by shouting skidoo and skidee at it, but the thing would not
move at all, and he finally from vexation threw the trick into the
fire and a new one had to be made. Very few can make it turn both
ways at will, and therein is the trick.

Take a piece of hardwood 3/8 in. square and about 9 in. long. On
one of the edges cut a series of notches as indicated in Fig. 1.
Then slightly taper the end marked B until it is nicely rounded as
shown in Fig. 2. Next make an arm of a two-arm windmill such as
boys make. Make a hole through the center or this one arm. Enlarge
the hole slightly, enough to allow a common pin to hold the arm to
the end B and not interfere with the revolving arm. Two or three
of these arms may have to be made before one is secured that is of
the exact proportions to catch the vibrations right.

To operate the trick, grip the stick firmly in one hand, and with
the forward and backward motion of the other allow the first
finger to slide along the top edge, the second finger along the
side, and the thumb nail will then vibrate along the notches, thus
making the arm revolve in one direction. To make the arm revolve
in the opposite direction--keep the hand moving all the time, so
the observer will not detect the change which the hand makes
--allow the first finger to slide along the top, as in the other
movement, the thumb and second finger changing places: e. g., In
the first movement you scratch the notches with the thumb nail
while the hand is going from the body, and in the second movement
you scratch the notches with the nail of the second finger when
the hand is coming toward the body, thus producing two different
vibrations. In order to make it work perfectly (?) you must or
course say "skidoo" when you begin the first movement, and then,
no matter how fast the little arm is revolving when changed to the
second movement you must say "skidee" and the arm will immediately
stop and begin revolving in the opposite direction. By using the
magic words the little arm will obey your commands instantly and
your audience will be mystified. If any or your audience presume
to dispute, or think they can do the same let them try it. You
will no doubt be accused of blowing or drawing in your breath, and
many o