Improvements in spirit levels or angle indicators

摘要

446,934. Level indicator. LYONS, E., 29, Phillip Street, Darwen, Lancashire. March 28, 1935, No. 9648. Drawings to Specification. [Class 97 (ii)] A bubble tube is in the form of a semicircle of glass tube stoppered at both ends and is attached to a wooden or metal frame, marked in degrees, which is attached vertically to a base. For attachment to aircraft the instrument may be pivoted to allow of measurements of inclination to be made in any direction.