the glass, which takes the
same position to the observer as the one in the rear. Thus a plain
aquarium is set in the rear part and one with swimming fish placed
in
[Illustration: Four Electric Magic Boxes Complete for Use]
the front, and with the proper illumination one is changed, as it
appears, into the other. When using as a window display, place the
goods in one part and the price in the other. Many other changes
can be made at the will of the operator.
Electric lamps may be controlled by various means to produce
different effects. Lamps may be connected in parallel and each
turned on or off by means of a hand-operated switch or the button
on the lamp socket, or if desired a hand-operated adjustable
resistance may be included in the circuit of each lamp for
gradually causing the object to fade away or reappear slowly.
Instead of changing the current operated by hand, this may be done
automatically by connecting the lamps in parallel on the lighting
circuit and each connected in series with a thermostatic switch
plug provided with a heating coil which operates to automatically
open and close the circuit through the respective lamp.
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