Diagram of a Horizontal Sundial

The image features a rectangular frame containing a semi-circular arc at the top and radiating lines extending toward the base. Arabic and Roman numerals (3, 4, 5, 6, 9, 10, 11, 12, 1, 2) are distributed along the perimeter of the rectangle to indicate hours. A single vertical line bisects the center, extending upward from the midline of the rectangle, representing the shadow-casting gnomon.

This diagram belongs to the early modern tradition of mathematical astronomy and horology, reflecting the period's reliance on geometric methods for measuring time through solar movement. It illustrates the practical application of natural philosophy as applied to the construction of timekeeping devices.