There are few commercial activities founded more completely upon physics than is the optical industry, but this foundation is very old, and the consequences are not altogether good. The foundation began perhaps with Huygens and Newton, followed with Young, Fresnel. and Fraunhofer, with a special debt to Maxwell. Helmholtz provided knowledge of the optics of the eye upon which the modern spectacle industry may be said to be built, but it was not until Ernst Abbe that a physicist really got busy and did something directly for the optical industry. Before his death in 1905 Abbe had developed an optical industry centering at Jena which was founded upon excellent and sophisticated physics of the period, and which for a long time dominated optics in the rest of the world. In fact so much good scientific material related to optics was assembled that the whole optical industry coasted, in a sense, for more than a quarter of a century, using up the research of the past.