Before the invention of the mechanical clock, the sundial was the main device by which people determine the time. They consist of a dial and a rod, the shadow of which, moving across the dial due to the movement of the Sun across the sky, shows the true solar time. In the Northern Hemisphere, shadows move in what we call "clockwise" during the day. According to a completely logical idea of the inventors of the first mechanical watches, the hands of a mechanical watch were supposed to imitate the movement of a shadow in a sundial. If mechanical watches were invented in the Southern Hemisphere, the clockwise direction would most likely be the opposite.