National Geographic : 1933 Nov
THE NATIONAL GEOGRAPHIC MAGAZINE ROLLING LENS GLASS AT ROCHESTER Poured on a heated steel table, the molten, white-hot material is flattened out with a huge motor-driven, heated steel rolling-pin. When it hardens sufficiently, the resulting pancake of glass is pushed into one furnace and then another until the annealing process is completed. rnotograpns courtesy Bausch and Lomb Uptical Co. REMOVING GROUND LENSES FROM GRINDING BLOCK AT ROCHESTER It is fascinating to follow the scores of operations through which perfect eyeglass lenses are produced. From the pouring of the glass, the cutting of the squares, and the curving of the lenses to the grinding and the testing, the thoroughness of the processes is matched only by the vast output of the factory (see text, page 568).