Oddly Powered Clocks.>
CORNELIUS DREBBEL'S CLOCK
Cornelis Drebbel- the same man who is suppose to have rowed a boat underwater up the Thames- built a device in 1610 which was apparently a clock telling the time, date, and season. The gold machine was mounted in a globe on pillars and appears to have been powered by changes in air pressure. So far I have found no details of this.
COX'S BAROMETRIC CLOCK
In the 1760s the well-known clockmaker Mr James Cox developed a clock which was were wound up by changes in barometric pressure. The work was done in collaboration John Joseph Merlin, with whom Cox also worked on developing automata. Two large glass vessels containing no less than 68 kilograms (150 pounds) of mercury were connected together by an ingenious system of cords an pulleys so that the pulleys would rotate back and forth as the atmospheric pressure rose and fell. A sector-and-pinion mechanism converted this to unidirectional motion so that winding occurred on both rising and falling pressures. Cox claimed that his design was a true perpetual motion machine, which of course it was not.
Cox was a well-known clockmaker. He showed his self-winding clock in a private museum along with other fine clocks. When he died in 1788, a Mr Thomas Weeks bought the clock for his museum. It stayed in his museum until the 1830s, when it was sold, and disappeared from view until it turned up again on public display in 1898.
Cox's clock is currently in the Victoria & Albert Museum in London, and one of these days I mean to go and track it down. Remarkably, there is no image of it so far as I can tell.
The images in this section were very kindly provided by John Howell.
Left: The back of a Puja clock made by the German firm of Jauch and Schmid.
*A remontoire, from the French 'remonter' (to rewind) is a spring or gravity reserve of power that can be configured to give a near-constant driving torque because it is rewound at frequent intervals from another power source- usually this was a mainspring, whose own torque would slowly decrease as it unwound. The idea was that rewinding a spring or lifting a weight at relatively frequent intervals isolated the escapement from the variable torque of the mainspring.
Left: Advertising material for the Puja clock movement.
To save you the trouble of grappling with a German-English dictionary, here are the translations of the salient words in the advert above; "wechselström" means "alternating current", "gleichström" means "direct current", "thermo-aufzug mit glaskolben-laufrad" translates as "thermo-lifter with glass bulb impeller", and "gehwerk" as "movement".
Left: Another Puja clock movement.
THE ATMOS CLOCK
Anyone interested in oddly-powered clocks will have heard of the Atmos clock, which is driven by changes in temperature. Find out more via these links: