Horizontal sundial, 1718. Made by William Deane.
© Science Museum / Science & Society Picture Library
Horizontal sundial, 1718. Made by William Deane of London. A typical horizontal sundial for use in gardens, it has an ornamental gnomon for a latitude of 51.5 degrees (that of London) and is divided to read minutes. Inside the hour circle there is a graduated circle of dates with a ring of figures giving the 'equation of time' for each date, the difference between mean or 'clock time' and sun time.