Black mystery clock, 1930s

In depth

By the end of the 1930s – following the passage of the Electricity Supply Act 1926 – nearly two-thirds of British households had frequency-controlled mains power direct to their homes. This opened new frontiers for household electricity, while also creating a new potential timebase for the nation’s clocks. Though companies such as ATO and Bulle (in France), Bentley in the UK and Eureka (internationally) had previously experimented with battery-powered clocks for domestic markets, mains supply opened a new mass market for synchronous mains clocks that were simple to use and promised to run for decades without servicing. Their success was such that housebuilders were soon installing dedicated sockets to accommodate the mandatory electric clocks high over the kitchen sink, and over the living room mantelpiece.

Having conquered the market in speedometers in the 1910s and 20s, the British firm Smiths was poised to seize the initiative in synchronous mains clocks. A report published in The Watch and Clockmaker in December 1931 claimed they were already producing 1,000 synchronous clocks a week from their Cricklewood factory, as well as supplying electric movements to other clockmakers. These two clocks are examples of the synchronous Smiths ‘Mystic’ model, in walnut wood and chromium, with glass dials, dagger hands and painted Arabic numerals. The movement was patented by Swiss firm Jaeger and issued to Smiths under license from 1934; it was produced in large numbers, as attested by the number of examples that survive.

The chromium casings came in a range of muted colours – though green and black, as here, were the most common – and the dial was occasionally also presented in a stepped wooden surround. The painted Arabic numerals and dagger hands are characteristic of the Art Deco style then in vogue.

The ‘mystery’ clock or watch – so called because it appears impossible to identify what moves the hands – was a popular novelty in the nineteenth century, particularly in France, where many examples were made by watchmaker and illusionist Jean-Eugène Robert-Houdin (1805-71). Mystery pendulum clocks to a different design were later manufactured by the German firm Junghans. The Smiths model was retailed as the ‘Mystic’ (possibly because the company were already manufacturing a longcase clock called the ‘Mystery’) and it represents an early example of the concept being adapted to the conditions of mass production, and the requirements of the synchronous motor – an idea that would gather new momentum in the 1940s, particularly in the USA, where further iterations on the idea were manufactured by the Jefferson Electric Company [see TCW 3022] and Haddon, both based in Illinois.

However, while these clocks (and many of their nineteenth-century antecedents) functioned via the invisible rotation of the round glass dial, the modish square shape of the Smiths clock makes this trick impossible. Instead, there is a third pane of glass between the front of the clock and the back – obscured by the mirrored bezel around the dial – and this is made to rock gently, via ratchet work in the base, which is connected to a motor reducing the mains speed of 200 rpm down to one rpm. It is the rocking of this glass that ultimately causes the hands to move forward once a minute. The result, as reported by T. R. Robinson in the Watch and Clock Maker for April 1935 was ‘a remarkable combination of practical and fanciful […] a domestic timepiece of great charm’. The Smiths Mystery Clock was a playful conversation starter for guests, but its mute challenge also reflects on the recent innovation of the mains synchronised clock itself, which must have seemed like magic to many.