23 VACUUM MACHINERY AND PARTS AND ACCESSORIES THEREOF FOR USE IN CONNECTION WITH SMELTING, MELTING, CASTING, ANNEALING, SINTERING, DE-GASSING AND DISTILLATION OF METALS AND FOR IMPREGNATION, DISTILLATION, DRYING AND THE COATING OF EYE AND SPECTACLE GLASSES, LENSES AND OTHER OPTICAL GOODS WITH THIN FILMS FOR PRODUCING REDUCED OR INCREASED ABSORPTION OR REFLECTION