[Illustration]
Mr. Panky, in showing his Gallery of Art to some friends, suddenly
directs attention to a painting of a saint, upon whose head a mysterious
and divinely golden light seems continuously to glow. To add to the
bewilderment of the gazers, the light suddenly ceases to descend, and,
in a twinkling, emanates from the saint’s head in a magnificent nimbus.
There is no resemblance to electric light or any other known, and the
undulating motion is incomprehensible under natural laws.
_Explanation._—The painting is set in a small frame in the centre of a
larger one.
At the back of the picture is a cogged wheel, of which the teeth move a
series of pinions. In each of these latter is immovably inserted one end
of a white glass rod, around which runs a spiral thread of gold (colours
may be substituted), and its other end terminating in a point. These
points work freely in sockets on the rim of the larger circle, equally
distant, to which, consequently, they diverge.
[Illustration: Fig. 144.]
When the cogwheel turns the pinions the glass cylinders revolve, and the
spiral lines change their position continually to the vision, and, as
the wheel turns to the left or right, the light seems to run up from or
flow down to the picture.
[Illustration]