Chinese myths relates that a 'south pointing chariot' was developed for guidance either in fog or acros featureles deserts. Examples were later displayed in ceremonial parades. This model shows a differential gear train connecting independently rotating wheels that maintains a pointer indicating a set direction. Though theoretically feasible this device would have been impractical over any distance. This conjectural model was constructed by George H Lanchester.
© Science Museum / Science & Society Picture Library