The San Francisco call., 1896-02-09

rises slightly in the air, and then falls
back to the ground and continues it's revo-
lutlonS. In another variant Zig. 27) the
spring Is also beneath, but forms part of
support upon which the top is capable of
continuing to reyolve. | have also spring
top Gig. 2S) that is very well balanced and
spins for long time. The helix has like
wise been applied to the setting of tops in
motion. The "Archimedes" top Gig. 29)
is simple disk provided with point. A
traveller forces it to descend along the helix,
from which it escapes in revolving. In
another top, called the Alternative" the
motion is inverse, and it is the helix that
IS displaced vertically Fig. 30).
In the class of compound tops are the
following:
l. Acoustic Tops-Among the tops that
have arranged in the first class, all those
that are hollow produce more or less
acoustic effects. They whistle, sing or
hum under the action of the air in the
aDertures with which they are provided.
In the wooden pegtop Gig. 81, a
variant of No. 2 the play of reeds is at the
upper part, and the spinning of the top
produces draft of air through properly
arranged apertures. The same is the case
IN top 81, the cheap model OF the shops.
The play of reeds is here in the interior.
In model 80 the axis is independent
OF the body of the top. 1t carries a fly
Wheel winch Is provided with wings, and
that revolves in the bell-shaped portion.
The harmonic or 'schoral" top Zig.
3D produces changing tones. The prin-
ciple OF model IS is different. The axis
terminates in a sort of claw that renders
it immovable, and a revolution of the top
is established upon the axis that remains
fixed. The latter carries a tongue that
strikes play of reeds carried by the top,
and the result is an air analogous to that
nar ,t,cia t1ae, ar11 L
of "rivoltellas."
2. Optical Tops-I mention in the first
place the spectral TOP Gig. 36) serving
as an advertisement to Pears soap. It is a
simple cardboard disk carrying lines fig
ured in black upon white ground. When
set in motion in good light, the concen-
trio circles assume the colors of the spec
trum, and the order of which is reversed
according to the direction of revolution.
The "chameleon" top Gig. 80 was one of
the first to popularize the effects of the
Helmholtz colored disks. 1t is a spring
top. The top shown in Fig. 38 is what is
called the ''dazzling" top. What is called
the enchanting" top Gig. 39) lends itself
to various optical experiments. The point
revolves on support, and, thanks to this
arrangement, the rotary motion and
3. Tops Producing Magnetic Effects
The Induction" top Gig. 4o) has already
been described in these pages, as has also
the "magneto-electric" one Zig. All. The
"Sultan" top Gig. 42) is small one with
very light spring. After it has been set
spinning there is placed near the axis
magnetized bar to the rounded end of
which it adheres and continues its revolu-
tion while suspended in the air.
4. Tops Producing Dynamic Effects
The hydraulic" or ,'water-jet" top is
shown in Fig 49, and the ''screw-spin-
ming" top in Fig. a.. The "puppet" top
Zig. 45) consists of a disk set in revolution
upon pivot by means of a movable handle
and cord. Above is suspended iointed
puppet made of cardboard. The project
ing radii of the disk strike the feet of the
figure and cause it to dance a sort of Jig.
Fig 46 represents the "carrousel" top. a
small table carries the carrousel, upon the
axis of which there is a disk provided with
bristles. The top being in its equilibrium
of revolution the carrousei is placed near
it, when the circular brush rubs against
the striated conical portion of the top, and
the carrousel enters into rapid motion to
the musical sound of the top, which is pro-
vided with a play of reeds.
5. Various Tops-The 'sgyrograph" top
{ Fig. Az consists of metallic disk of some
little weight elevated upon quite long
point formed of sharpened lead pencil.
The top is spun upon sheet of paper and,
as it is difficult for it to assume vertical
equilibrium, the pencil point draws spirals