| Year | 1931 |
| Date | 22-Jan |
| Volume | 64 |
| Issue | 1,550 |
| Page | 92 |
| Category | Exhibition |
| Part | |
| Title | Exhibition of Scientific Instruments. The Physical Society and the Optical Society, London. Prizes for Apprentices and Learners |
| Author | |
| Notes | Research exhibits, synchronous electric clock, rectifier ammeters and voltmeters, woven resistance units, introscope, pneumatic electric lamp, home cinema machine, optical and kinematograph lenses, rectifiers for alternating current |