Clock rewound with hydrogen gas by Pasquale Andervalt

Clock rewound by hydrogen gas by Pasquale Andervalt, Trieste, Italy, c.1835. Brass skeleton-type frame. Enamel dial with open centre to expose the mechanism. Steel hands. Pin-wheel escapement and decorative gilt pendulum. The clock is mounted onto a large red glass cylinder, and above the movement is a tubular coiled brass magasine. The glass cylinder is designed to hold a solution of dilute sulphuric acid, and the coiled brass tube to contain zinc pellets.

The next best thing to ‘perpetual motion’. As the driving weight nears its lowest position, a zinc pellet is triggered to release into the sulphuric acid, resulting in the production of hydrogen gas within the glass cylinder. The build-up of hydrogen in the jar drives a piston upwards, thereby rewinding the movement. This winding process is slow, and while it is taking place the smaller brass weight acts as a maintaining power and keeps the clock going. Once the clock has finished its winding cycle, the hydrogen gas is released from the cylinder.

According to the acquisition notes of the Worshipful Company of Clockmakers, a Mr William Wing presented this clock to the Company in 1874, which is described as 'a very elegant and complicated Clock of a novel construction which was exhibited at the Great Exhibition of the Industry of all Nations 1851.' The exhibition catalogue describes three clocks as having been exhibited by Andervalt, with the claim that they would go for 20-30 years without ever needing to be wound up. Clockmakers' Museum No. 626.