See Helix Helios at <http://www.egeskov-slot.dk/map/sun_dial.html> for a wonderful helical dial by Piet Hein. It is at Egeskov Castle in Denmark. Thanks Daniel Roth for including it on "sundial links"
Roger Bailey At 05:07 PM 8/28/98 +0100, Les Cowley wrote: >David Higgon's solution and mine reduce to a good approximation to > > Length ~ (w*A/(4*pi)*sqrt(A^2 + 1) = (R/2)*sqrt( (2*pi*R/w)^2 + 1) > >where w is the distance between successive turns, A is the total rotation >angle of the spiral in radians and R is distance of the outer end from the >centre. > >To make this on topic, can we please have a dial based on an Archimedian >spiral! > >Les Cowley > >
