Let's go back to Damascus for a less euro-centric perspective on this question. In a previous discussion Gianni reported his research and conclusions on the introduction of the polar gnomon. He attributed it to Ibn Al-Shatir and the sundial at the Great Umayyad Mosque in Damascus in 1371. Ibn Al-Shatir also introduced a sundial compendium, a small universal polar sundial that incorporated a magnetic compass for orientation.
Al-Shatir was a genius in math and astronomy who made many contributions to science but what was his day job. He was the timekeeper "muwaqqits" at the Mosque responsible for setting the times to pray. In that role he was responsible for the other amazing timepiece at the mosque, the mechanical clock. This ancient water clock kept equal hours striking at each hour. The sundial and clock complemented each other to give accurate time with equal hours. See http://www.muslimheritage.com/topics/default.cfm?ArticleID=685 for one reference to the clock. See http://en.wikipedia.org/wiki/Ibn_al-Shatir for references to Ibn Al-Shatir. Regards, Roger Bailey ----- Original Message ----- From: "Frans W. Maes" <[EMAIL PROTECTED]> To: "Frank King" <[EMAIL PROTECTED]> Cc: "Sundial" <[EMAIL PROTECTED]> Sent: Friday, August 22, 2008 12:46 AM Subject: Re: equal and unequal hours > > Dear Frank (King), > > Frank King wrote: > >> No doubt the transition to equal hours (whether >> starting at noon, midnight, sunrise or sunset) >> was gradual but I feel it long predates mechanical >> clocks. > > Do you have any evidence supporting your feeling? > > I have studied the question when the pole-style sundial, reading equal > hours, appeared in the Western world. Zinner appeared to be the most > important reviewer of the few written primary sources. My conclusion was > that the pole-style dial appeared around 1400, hence a century or so > AFTER the introduction of mechanical clocks. > I have written an article about this (in Dutch ;-) for the Dutch and > Flemish bulletins in 2004. > > It has been suggested that the pole-style dial (and hence equal hours) > was brought to the West by returning crusaders. Karlheinz Schaldach gave > convincing arguments against this in BSS Bulletin 96.3. > > Best regards, > Frans Maes > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.138 / Virus Database: 270.6.6/1627 - Release Date: 22/08/2008 > 6:48 AM > > > --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
