1,058,716. Slide projectors. C. BRAUN and W. BRAUN. Oct. 18, 1963 [Oct. 24, 1962; March 14, 1963], No.41322/63. Heading G2J. The magazine of a slide projector is driven by an electric motor 2 through a transmission system comprising first and second gears 27, 27' driven in opposite senses by the motor and means for selectively making a drive connection with one or other of these gears to give a forward or reverse motion to the magazine. A lever 15 pivots about shaft 16 under the action of electromagnets 26, or 26' so that pinion 13 mounted on the lever selectively engages constantly driven gears 27, 27'. Crank disc 8 meshes with pinion 13 and is driven in the selected direction to operate the slide charging mechanism comprising connecting rod 6, coupling members 4, 5, and slide mover 3 as described in Specification 1, 058, 715. As disc 8 rotates striker member 9 turns pinion 10 mounted on spindle 11 by one tooth and so advances the slide magazine by one slide width through a rack and pinion connected (not shown). A plate 22 acts on lever 15 by means of projection 23 and spring 14, and the electromagnets move levers 19 or 20 through rods 25, 25', the levers each being connected to plate 22 through spring 24. For forward or reverse drive, the lever 19 moves clockwise or anti-clockwise about pivot 39 and is locked in either displaced position by projection 33 on pivoted lever 34 so that pinion 13 is held against the selected gear. Lever 19 is released when rod 6 on its return stroke depresses end 34' at lever 34 as in Fig. 1. Pinion 15 then returns to its neutral, disengaged position as shown. The magazine may then be moved manually by rotation of knob 37 on spindle 11. The gear teeth are preferably of moulded plastics material. The continually running motor 2 drives a cooling fan. In a modification, lever 15 is moved about its pivot 16 by direct action of the electromagnets, levers 19, 20 being dispensed with.