Like silent sentries, the three motion picture projectors stand ready to deliver the next film presentation. The 35/70 machines have Carbon Arc lamps. The 16mm machine is Xenon lighted. The magnet readers are stored above the Ballantine pre-amplifier and changeover boxes between the machines. The marks on the floor are where operators standing in the same spot has worn the battleship linoleum. The white pipe on the wall is insulated for cooling water in the lamps and projector apertures.