Two D.V.L. Instruments: The Scratch Recorder for Measuring Variations in Length and the Wing‐Vibration Recorder

ONE of the activities of the Deutsche Versuchsanstalt für Lufthfahrt has, naturally, been directed to the development of special instruments adapted for the peculiar needs of the experimental work carried out at Adlershof. Arrangements have recently been made whereby a wide range of these instruments is available in England and they can now be obtained from International Technical Developments, Ltd., of Thames House, Millbank, London, S.W.I.