With new experimental equipment already installed, the recently opened applied mechanics laboratory of the Engineering School will concentrate on photographic measurement of the elasticity of various substances, it was learned yesterday from J. P. Den Hartog, director of the laboratory.

No work in the field of Applied Elasticity has yet been done except with idealized structures; the Harvard experiments will be the first to measure the elastic qualities of actual structures, by means of photographing polarized light sent through models made of transparent celluloid. Stress is shown by varied colorings and patterns produced on a photographic screen by the light.

Other methods of measuring stress are being worked out by Mr. Den Hartog and his assistants, which involve the use of membranes, electricity, and water. The results of these stress experiments are expected to be of practical value in large building projects, enabling engineers more accurately to determine the strains which may be withstood by skyscrapers and dams.