Research and Test Apparatus

The Type 1400E sound level meter, claimed to be the first commercial fully transistorized unit of this type in the world, has been designed by Dawe Instruments Ltd., 99 Uxbridge Road, London, W.5. By replacing all electronic valves with transistors powered by built‐in dry batteries, the new instrument has been made fully self‐contained with an overall size of only 8¼ × 5¾ × 3¾ in. and a weight of under 4 lb. It can be operated readily with one hand while the other is used to note readings.