THE WONDERFUL ASCENDING GLOBES.
A box is produced with solid sides, and a hole in the upper part of the
front, enclosing a piece of transparent glass. On looking through this
aperture, there is apparently seen an inclined plane, up which,
in a serpentine groove, is seen a ball continuously rolling—no
sooner disappearing at the top edge than it reappears for a fresh
ascension at the bottom, and so on uninterruptedly.
Explanation.—The box is made of wood, with the long
sides about seven feet long, and the ends a foot square; the front half
of the top is of ground glass, admitting a dull, even light. The
interior is thus represented :—
The box is divided within into the three compartments, A, K, and H.
The compartment A, into which one looks by the eyehole 0, is enclosed
on both sides by solid walls painted with a fantastic design as of a
Gothic colonnade, in grissaille with black shading, lit by the light
passing through the ground-glass roof, L. The end B is painted the
same, but the archway is cut out; entirely, giving a view of the
chamber D, or rather of the plane mirror E. This mirror, set at an
angle of 30° or 40°, reflects through the opening I in the
floor the inclined plane F.
The chamber H is closed in on all sides with dead-black walls,
pierced only in the roof at I. A board, inclined at the same angle with
the mirror E, but at an angle opening from it, is solid, and has a
uniting groove upon it ending at top and bottom with holes, being
mouths of pipes leading off as marked into the chamber K. This chamber
K contains the following piece of simple mechanism:—
MNOP is a brass frame, holding the wheels Q R S T. Q is a drum with
a mainspring, which, when wound up, turns the other wheels, and finally
acts on the fly.
wheel T. The axle of the wheel R comes out beyond the frame, so that
the brass rod U X can be fixed to it. At each end of the rod is fixed a
metal box Z, the two being exactly alike, with a small movable brass
plate, Y, on a pivot, bent back as shown, so that a ball rolling down
the plane and by the tube containing the groove F, will fall into the
box past the plate, but must there remain until the movement of the
wheels shall have made the rod describe half a revolution. Then the box
containing the ball is brought to the top tube, into which it is
dropped, so that it must then roll down the plane, to be caught,
carried up, and sent downwards anew. This descent, seen inverted in the
mirror, has the appearance of being an ascent, and forms a most
excellent optical illusion. The ball should be of bone, ivory, or
bright silver, so as to be plainly perceptible in the light from the
lamp and its reflector G.
Variations.—In lieu of an inclined plane there may be a
column made of wire, through which the ball may be plainly seen running
; or two such columns turned round each other, so that one ball may
seem to be running through the other, &c.
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