抄録
It is pointed out that a correction should be made to the wall thickness of glass hollow ware when measured by the visual difference in position of reflected images of a light source, one reflected by outer, the other by inner surface of the wall.
A formula is derived for obtaining approximately the correction as a function of refractive index of the glass and ratio of observed thickness to radius of curvature of the ware, Over wide ranges of these variables, the correction is computed with the aid of the formula and an I. B. M. calculating, machine and the results are tabulated, a few special cases of which are shown by diagrams.
Indirect measurement without damaging the ware as mentioned above and direct measurement by breaking made on samples of varied refractive index, wall thickness and radius of curvature proved the usefulness of the prepared table of correction.
