I HAVE tried the following experiment: A piece of optically flat crown glass 3·5 cm. long, and 1·5 cm. broad and 0·3 cm. thick, was supported on wood at the extreme ends, and the middle was loaded with 6 kgm. applied by means of a wooden chisel edge, which carried a weight moving in guides above. It remained in position from April 6, 1938, to December 13, 1939. At the end of that time the glass was taken out and tested on an optical flat by means of interference fringes. It was found to have been bent, the sagitta of the arc amounting to 2·5 bands or 1·25 waves, that is, about 6 × 10–5 cm.
About this article
Journal of Micromechanics and Microengineering (2006)
Low-temperature deformation of fluoride and oxide glass fibers below their glass transition temperatures
Journal of Non-Crystalline Solids (1994)
Obituary Notices of Fellows of the Royal Society (1949)