The Praxinoscope: Moving Pictures in a Ring of Mirrors

Before cinema, moving pictures were toys. The zoetrope spun a strip of drawings inside a slotted drum; looking through the slots, you saw each drawing only for an instant, and the series ran together into motion — dimly, because the slots let in so little. Émile Reynaud of Paris patented the praxinoscope in France on 30 August 1877 (patent 120484). He replaced the slots with a ring of flat mirrors at the centre of the drum, one for each picture, set at half the drum's radius. The reflected pictures appear one after another in the same place, bright and steady. Reynaud went on to project them for audiences in his Théâtre Optique. This rung shows why the mirrors must stand at half the radius, and builds a praxinoscope.