Thank you very much for your many references and your bringing up Babylonian astronomy, which I had not considered. It is interesting that the Greeks seem to be influenced more by the Babylonians than by the Egyptians.
Since my earlier post I have read a bit more myself. Otto Neugebauer in "The Exact Sciences in Antiquity" refers to a sun dial described in the cenotaph of Seti I in 1300 BCE. But Marshall Clagett shows that this is actually the standard shadow clock, not a sun dial in the modern sense. He also describes a small vertical-plane sun dial (a 2.25" disk with 13 angle markings at 15-degree intervals) from Gezer (1224-1214 BCE). He discusses Ptolemy's analysis of the vertical gnomon. However, there is no direct mention of obelisks as shadow clocks or gnomens. Of course, any marks of hours on the ground could have easily been lost.
For you and others interested in Egyptian time keeping I recommend Marshall Clagett's authoritative source book "Ancient Egyptian Science, Vol. II, Calendars, Clocks and Astronomy," Memoir Vol. 214, American Philosophical Society, Philadelphia, 1995.
I have still found nothing linking Eqyptian obelisks to sundials or timekeeping.
Gordon At 07:42 8/21/04, Gianni Ferrari wrote:
I try to write some reasons for which I think that the Egyptians has never used the obelisks as sundials 3000 years before Greeks . Herodotus (484-424 B.C.) is the first author that makes mention of the gnomon with the meaning of sundial : "Greeks have learned from the Babylonians the polos and the gnomon, as the twelve parts and day" (Hist. II). The invention of the first sundials is often attributed to the philosophers Anaximander (610-545 B.C.) and Anaximenes (586-525 B.C.) but certainly the gnomon, simply made by a pole vertically fixed to a horizontal plane, was known and used by he Babylonians. According to some modern researchers (for ex. Szabo, Maula in "L' astronomie chez le grecs") it is almost sure that the gnomon was not used in the period 3-400 B.C. as element of a sundial but only as calendrical instrument - to find the beginning of the different seasons - and as astronomical instrument for the determination of the days of the solstices and of the equinoxes, of the length of the inter-solsticial arc (and therefore of the ecliptic inclination) and of the gnomonic equinoctial ratio (ratio between the gnomon's height and the length of its shadow at noon on the equinoxes) that was used in antiquity instead of our modern "latitude" (as in Vitruvius). Therefore the gnomon did, some century before our epoch, the same functions of the great camera obscura sundials built, as great astronomic hinstruments, in the XVII century. Almost certainly the sundials of Anaximander and Anaximenes, built for different purposes, could only mark the noon or the passage of the Sun on the Southern meridian . Gianni Ferrari 44° 39' N 10° 55' E Mailto : [EMAIL PROTECTED]
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