Ferguson's Paradox - the solution. Before leaving this subject, it is appropriate that one of Ferguson's orrery-type models should be mentioned, namely, the Mechanical Paradox.
Although this was a straightforward piece of mechanical hardware, it owed its origin to a theological discussion. Ferguson related the story in a very long letter to a friend, the Rev Mr Cooper of Glass, Banffshire, written many years later. The original letter does not appear to have survived, but Henderson printed it in full from a copy said to be in Ferguson's own hand; it had previously been printed in the Horological Journal for 1858. The essence of the story was as follows. One evening Ferguson went to a weekly gathering (probably a dining or drinking club), where one of the other people present, a watchmaker, 'began to hold forth against a Trinity of persons in the God-head, wondering at the impudence of the person who broached such an absurd doctrine'. CNC Cookbook: Astronomical Clock.
Notes on Constructing an Orrery / Antikythera Mechanism I've always had a great interest in Astronomy, and I read with great interest recent articles about the Antikythera Mechanism, which was apparently an ancient orrery or simulator of motions of the heavenly bodies.
The machine, which was constructed circa 80 BC, could represent the motions of most heavenly bodies known in its time using a clockwork consisting of 37 gears. Differential Gear Mechanism Was Way Ahead of Its Time... The front dial would show the progression of the Sun and Moon through the Zodiac according to the ancient Egyptian calendar.
The lower back dial gives the Metonic cycle, the Synodic cycle, and the Lunar year of 12 Synodic months. A Simple Lamina Flow Engine. A Simple Lamina Flow Engine I learnt of this engine, at an International Stirling Engine Conference, some years ago.
In discussions with Jim Senft he referred to it a Lamina flow engine, in US patents it is usually called an acoustical heat engine. Jim's explanation seemed, at the time, clear however on my return to the UK it was evident I had not fully understood the theory since I failed to get an experimental engine to work! Solar Heat Engines. Jerry E. Howell - Model Project Plans & Kits Home Page.