M-264 Advertising Slide for 1920's Projector, to be shown in public movie theaters during intermission. This glass slide, by the BELLEVUE HERALD, shows "N.Y.C. Train As She Looked 50 Years Ago". Original and Made by the National Slide Corp., Detroit, Mich. The slide is black and clear with sharp focus...and beautiful! The slide measures 4 inches by 3.25 inches. The photos I took don't do it justice! (This is one of two identical slides.