Hello Woody,
Your email as follows : ====================== It seems reasonably well established that the oldest extant sundials are from ~1500 BC in Egypt, but I recently came across the following statement in the popular book "Timekeeping" by Rodney Dale (1992): "Shadow boards are still used in Upper Egypt for measuring the time taken to perform tasks, or for timing the distribution of water for irrigation. A water clock is used to mark the movement of the shadow." (1) Regarding the first sentence, is this correct? Can anyone cite some other source of information on this practice today? (2) What does the second sentence mean?! ======================= I have some news for you. Down here in our local library (this is coming from 'down under') we have this set of the Colliers Encyc..( I think) and what it says about your first question is as follows : " The oldest sundial known was made about 1500 BC. It was fashioned from stone in the form of a bar about 12 inches long, with a vertical T-shaped piece fixed at one end. The hours were distinguished by marks cut into the stone at irregular intervals. It was fitted with a plumb for leveling. The T end was turned toward the east in the morning and toward the west in the afternoon. The position of the shadow of the upper edge of the T indicated the time..... " About the beginning of the Christian Era, the principle of the sloping gnomon was discovered." As for the second sentence, I would hazard a guess that water clocks in Egypt are 'recent'. According to my 'Timetables of History' it mentions that in the year 1090 AD " The first water-driven mechanical clock constructed in Peking." Also for the period 1500 BC - 1001 BC it mentions : " Obelisks in Egypt serve as sun dials " " Intricate clock, measuring flow of water found in tomb of Amenhotep III " " Height of sun in relation to incline of polar axis measured in China " Further in the period 700 BC - 601 BC we have " Water clocks in Assyria ". Period 600 BC - 501 BC we have " Sun dial (gnomon) in use in Greece and China." About 159 BC - " The first water clock ( clepsydra ) in Rome c.-159 ". I hope all this will help you out. I'm happy to be of assistance. Take it easy Amit
