Compass: The magnetic compass was probably first made during the Qin dynasty. Chinese for tellers used lodestone* to construct their fortune telling boards. Then someone realized that  lodestones were good for pointing real directions, leading to the first compasses.
        *A mineral made of iron oxide which aligns itself in a north-south direction.boussole-temple-r.jpg                                            images-2.jpg
Ancient Chinese Compass                                   Present day compass
                                                                                                                                           LB