Dear Frans, You ask a very perceptive question:
> > 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? No! I had heard (from you and others) that the polar-oriented gnomon was a much later development than one might guess, sometime around or after 1400 as you say. Also... I knew there were mechanical clocks at that time but I had frogotten that clocks had been around for a century or so by then. You are almost suggesting (perhaps you are actually suggesting) that the development of the polar-oriented gnomon was a consequence of the development of mechanical clocks. A polar-oriented gnomon is not, of course, essential for indicating equal hours. Indeed, Italian Hours are (almost) equal hours but you do not indicate Italian Hours with a polar-oriented gnomon. My thought (my feeling!) was that Gianni or someone else could suggest that sundials showing Italian Hours were around before clocks. His answer is clear: > The equal hours started to be used after the advent > of the tower clocks... This suggests that the advent of tower clocks was seminal to the popular use of equal hours and, I assume, this applies to ANY kind of equal hours system, whether the day started at sunset, sunrise, noon or midnight. Given the late development of the polar-oriented gnomon I had assumed that equal hours sundials starting at noon or midnight were around before the introduction of the polar-oriented gnomon. Is this a false assumption? You say: > It has been suggested that the pole-style dial > (and hence equal hours)... I wonder about the use of the word "hence"? You don't need a polar-oriented gnomon to indicate equal hours (starting at noon or midnight) although it certainly helps. I am in danger of going wildly astray! Maybe you could confirm (or refute) the suggestion that there were sundials that showed equal hours starting at noon or midnight before the advent of the polar-oriented gnonom? I promise not to challenge your answer :-) Best wishes Frank --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
