What is a Sundial?

Although the history of the sundial begins in the ancient world of Egypt, Greece, and Rome, the great age of dialing (as the art of making sundials was known in England) fell in the sixteenth, seventeenth, and eighteenth centuries, and it is chiefly the main instruments produced in these centuries.

The earliest time-measuring devices which have survived to the present day are the primitive sundials or shadow-clocks and the water-clocks of ancient Egypt. These types of instruments were developed and improved by the Greeks. They were in use through-out the periods of the Greek and Roman Empires. Together with the sand-glass they were still the only timekeepers generally employed throughout the Dark Ages and the early Middle Ages.

Medieval dials are extremely rare, but the profusion of styles and the ingenious variations concocted by the instrument makers of the seventeen and eighteenth centuries more than compensate for their comparatively recent date. The origins of these dials, often appearing independently in different parts of Europe, are very obscure and do not follow any obvious evolutionary line. It is frequently impossible to be precise as to their place or date of origin.

What is more certain is that they became far more widespread in the seventeenth and eighteenth centuries, for this period saw a rise in popular understanding of mathematics, and a great surge of interest in technology and popular science, which coincided with the development of relatively accurate clocks and watches. The combination of the two led to a wider interest in time, the methods by which it is reckoned and kept, and also in problems of accuracy. For checking the performance of a clock, however, there was no standard except that of the sun.

A sundial was therefore essential for the purpose of time measurement. Instrument-makers quickly produced dozens of types to meet demand. Larger sundials, designed to be fixed in a garden, on the wall of a building, or kept in one location were also produced in quantity.

One of the most interesting sundials is that of the Universal Equinoctial Ring Dial!