A stone block of alabaster, which is called a sundial to know the time of day in ancient Egypt, where this piece is of the type that tells us to measure the time of day depending on the extension of the shadow and the angle of the direction of the shadow, as it is a block with a slant face with a series of oblique and parallel lines inscribed on its face to distinguish the time

“The significance of this piece is that it is roughly one thousand years older than what was generally accepted as the time when this type of time measuring device was used,”

Susanne Bickel says another option of the University of Basel in Switzerland. Past sundial discoveries date to the Greco-Roman period, which lasted from about 332 B.C. to A.D. 395.

The sundial is made of a flattened piece of limestone, called an ostracon, with a black semicircle divided into 12 sections drawn on top. Small dots in the middle of each of the 12 sections, about 15 degrees apart, likely gave more precise times.

A dent in the center of the ostracon likely marks where a metal or wooden bolt was inserted to cast a shadow and reveal the time of day.

Bickel and her colleagues aren’t sure for what purpose the workmen would’ve used the sundial, though they suggest it may have represented the sun god’s journey through the underworld.

“One hypothesis would be to see this measuring device in parallel to the illustrated texts that were inscribed on the walls of the pharaohs’ tombs and where the representation of the night and the journey of the sun god through the netherworld is divided into the individual hours of the night,” Bickel wrote. “The sundial might have been used to visualize the length of the hours.”

The device may have also been used to measure work hours. “I wondered whether it could have served to regulate the workmen’s working time, to set the break at a certain time, for example,” she said. However, Bickel noted, a half-hour wouldn’t mean much to these people.

Ptolemaic period

The Metropolitan Museum.