Valendas, 18th century
Sundials show the time of day with the help of the position of the sun. Portable models in the form of rings, so called farmer’s rings, were widespread among the rural population because of their small size and simple operation.
On the inside of the ring sundial the hours are marked, on the outside the months. For telling the time the middle ring with the pinhole is turned to the current month. Then one lets the clock hang from the chain and turns it to the sun so that the sunlight falls through the hole and shows the time on the inner scale. At night and in bad weather sundials were useless.