Signedplate on base: plate on front: CENTRAL SCIENTIFIC CO. / TRADE MARK / LABORATORY (CENCO logo) SUPPLIES / APPARATUS CHEMICALS / REG. U.S. PAT. OFF. / CHICAGO, ILL
Inscribedplate on base: BATTERY
FunctionThis appears to be an alternating current (AC) motor demonstration. The devices at both ends of the board are electric motors, and the device in the middle is the AC power source. It appears that one would connect a battery, which gives direct current, to the generator at the center, and turn the wheel to produce the alternating current. Depending on the speed of the central wheel, the motors on the sides would turn at different speeds. The two motors will also turn differently for having a different number of coils.
ProvenanceCruft Laboratory, Harvard University.