A woman checks machine parts on a contour projector. The part is matched up against an original blueprint. A magnetic gauge checks thickness of enamel. Oil is used to measure sizes of curved shapes in jet plane manufacture. Man plays a trumpet. A stroboscon turns the sound waves into harmonic read outs. Woman checks smells in a telephone receiver type contraption. Woman assembles a machine for measuring power of light bulbs. The light meter tests bulbs.