Dear Membership, Sundial interval timers seem to be an area that is not well documented in the documents I have access to.
One type of interval timer is a basic triangular wedge of some thickness. When the light is just extinguished on one edge til it just lights up the other ( when in the equatorial plane ) indicates the solar time equal to the angle included. 30 degrees, a 6th of a circle would time two hours, Half that slice or 15 degrees would time an hour. Could it be that pie was invented and in some places eaten last so that, in the sun, it could time out the lunch hour?? An equilateral triangle times out 4 hours. Two of them with a triangular gap between them time out a work day with time off for lunch. Could so many of the triangular markings we see on old sites be interval timers of some kind? What seems to be neat to me is that it doesn't matter whether the sharp end or the blunt end of the triangle faces the sun. When the blunt end faces the sun, a finger held up on the circumference would, when it casts its shadow on the tip of the pie, give an indication of how much lunch hour is left. Long, long ago, I won a bet with my dad by placing a small mirror tile a long way from our house and getting the reflection to sweep from one end of our house to the other in exactly one minute. Later I placed a dowel in a Christmas tree base and with a blob of modeling clay at the top repeated this for several intervals of time. The moon, when it is half full, subtends about a quarter of a degree which movement is about 1 minute. ( unfortunately the width is not in line with it's movement ) A piece of tape, the edge of a building and a fixed viewing point could time a 3 minute egg at midnight?? Write me if you have any documentation regarding this. Especially ancient records of interval timers. Thanks much! Edley McKnight [43.126N 123.357W]
