JEAN-LOUP CHARMET / SCIENCE PHOTO LIBRARY JEAN-LOUP CHARMET / SCIENCE PHOTO LIBRARY
Sundial. Portable, ivory sundial with a built-in magnetic compass (at lower centre). The sundial measures time using a shadow formed by a needle (at upper centre). This shadow moves across the face of the sundial as the Sun moves across the sky; the lines on the sundial each correspond to a certain time. The magnetic compass is used to correctly align the sundial before use. Portable sundials like this were superseded by the development of cheap, reliable watches. Ivory is made from the tusks of elephants or walruses.
Model release not required. Property release not required.