Thomas Young
(1773-1829)

Thomas Young was an outstanding English scientist who did pioneering work in optics, sound, impact, and other subjects. He observed that applied torque is balanced by shear stresses on the cross section and that the shear stresses are proportional to the distance from the axis.

From Mechanics of Materials, 4th Ed., by J.M. Gere and S.P. Timoshenko, PWS Publishing, 1997, pp. 835-42.