This equatorial sundial is portable, easy-to-make, and can be adjusted to any latitude between 25 and 50 degress. It works because, when oriented properly, the top section simulates the earth's equator. When the sun is above the equator -- as it is from March 21 to September 23 -- It is above the top section of the sundial and will cause a shadow to be cast on the upper face. When the sun is below the equator, it is below the top section of the dial and will cause a shadow to be cast on the lower face. To tell the time, all you need to do is observe where the shadow falls.

Before mechanical clocks were invented, sundails were an important way of telling time. The first sundial is believed to have been used in Babylon around 2000 B.C. over the centuries, these solar time machines have been made in every conceivable shape and form. There have been vertical sundials and horizontal sundials. Sundials of stone, wood, silver and gold. During the Renaissance, some sundials were made in miniature pocket versions and were even set into pistol butts and finger rings.