The object in the image is a portable brass sundial, commonly known as a pocket sundial. 9 x 7 cm With leather box. Material: They are generally made of brass or other durable metals. Function: They use the position of the sun and the shadow cast by a gnomon (the raised central piece) on a graduated scale to indicate the time. Design: They often feature intricate decorative engravings, such as celestial motifs, animals, or coats of arms. History: These instruments were very popular between the 16th and 18th centuries as portable scientific tools for measuring time.