Title: Control of Double Images in Automobile Glass
text: This paper first examines the optical principles involved in the formation of double images so that glass may be evaluated for this property in the design stage of automobile windshields. It then describes a new instrument, the local curvature and wedge meter, which has proved to be useful in determining the extent to which each of the three factors of curvature, inclination, and wedge has contributed to the presence of double images.