The Synchronome Clocks


Dollar Museum is fortunate to hold two early Synchronome Master Electric Clocks. Each of these clocks was used to remotely operate the William Spence Memorial Clock, which was erected in 1912 by the people of Dollar to commemorate the life and untimely death in 1910 of Dr William Spence, the much loved and respected local doctor. [See separate article on Dr William Spence and the Memorial Clock, click here].

Synchronome No. 348

The Upper Room of the museum holds the original Synchronome clock, number 348, which was installed in 1912 within the Dollar Council offices on Bridge Street to remotely operate the Public Clock at the bridge. It was officially inaugurated on 23rd October 1912. [image shown on left] Due to its eventual malfunction this clock was replaced by another Synchronome clock, number 337, also in the museum.

Downstairs, near the museum entrance is situated the other Synchronome clock, which was a replacement for the original Synchronome clock installed in 1912 within the Dollar Council office to remotely operate the Public Clock at the bridge. This clock was bought by Dollar Council sometime in the 1950’s from the pawn shop of Messrs. Smellie & Weir, Coalgate, Alloa, where it had served as a shop clock and also drove a slave dial outside their premises. This clock’s serial number is 337. [image shown on right]

The two master clocks and the Memorial Clock were supplied and fitted by Dyke Brothers, of 11 Royal Exchange Square, Glasgow, Jewellers, Silversmiths and Clock Factors (which ceased business in 1943).

We are grateful for the rescue of both these master clocks for the museum on the dissolution of the Borough Council in 1975, by the then Borough Clerk, Mr. Graham.

Both clocks, now in the care of Dollar Museum, were lovingly and painstakingly restored by Mr Robert L. Lindsay; clock number 348 in 1989 and clock 337 in 1990. He made new parts to replace those missing – namely the pendulum rod, bob and support, trunnion, and gathering pallet.

In turn, these clocks were replaced by an electric motor type movement, which still drives the Memorial Clock today.

Synchronome No. 337

The William Spence Memorial Clock has four dial faces, and the originals were synchronized by an electrical pulse, wired to the Synchronome master clock in the Burgh Council office on Bridge Street. The four clocks were ‘slave’ clocks. The photograph of the 30 inch, opal (for better illumination), clock faces shows the maker’s name (Synchronome) and the name of the supplier – Dykes Bros of Glasgow.


Both clocks were manufactured in 1912 by the Synchronome Company, which began its existence  in 1895.

Frank Hope-Jones was born in 1867 at Birkenhead, on the Wirral, and was fascinated by the uses of electricity.  Other family members were also interested in the uses of electricity. His brother Robert was a pioneer in the field of electric organs.  Robert helped with early experiments adapting clock movements. Then Frank met George Bennett Bowell when they were working at the electric organ factory of his elder bother, Robert. Both men were passionate about electric clocks and spent much of their spare time building them. Hope-Jones and Bowell made a number of electric clock inventions  and by 1895, had taken out their own patent which included the Synchronome switch.

They formed their own Synchronome Syndicate Company in 1897 and moved to London. They intended to float their company on the London Stock Exchange, but when this venture failed Bowell left. Frank Hope-Jones continued to work on improving the clocks and developing his business, which was only finally incorporated in 1912.

His company, The Synchronome Co. Ltd., was based at  32–34 Clerkenwell Road, London. Interestingly, the company took their time signal from Greenwich Observatory, which was transmitted via General Post Office telegraph wires.

The Synchronome clock was a precision pendulum clock that was developed in the late 19th  and early years of the 20th century primarily by engineer and clockmaker Frank Hope-Jones. The Synchronome system went on to become the basis of the most accurate pendulum clocks ever produced. The name Synchronome has its origins in Greek: syn (with), chronos (time) and nomos (law) meaning ‘with the law of time’.


Frank Hope-Jones
(courtesy of Synchronome Clocks)
Synchronome Company offices, Clerkenwell Road, London
(courtesy of Synchronome Clocks)

The key innovation of the Synchronome clock was the use of an electrical impulse to keep the pendulum in motion, rather than the traditional method of using a mechanical escapement. The electrical impulse ensured a more constant and precise oscillation of the pendulum, leading to greater accuracy in timekeeping. The principal of the design was to reduce friction to a minimum and so the pendulum of this clock was free except when receiving an impulse from a gravity lever twice per minute. It operated from a 4.5 volt DC electrical supply.

The clock kept time by using a gathering arm from the pendulum to engage a fifteen-toothed wheel every two seconds. Once each half-minute, the toothed wheel completed a rotation and a vane released a gravity arm which gave a gentle impulse to the pendulum. As the gravity arm fell, it made an electrical contact, completing a circuit with an electro-magnet to reset the gravity arm. By placing a relay in series, slave clocks could be driven. It was the reliability of the electrical contact in the Synchronome design which set it apart from earlier electric clocks. The combined electrical/mechanical design of this clock made it a most accurate mass-produced clock.

Sending impulses through electric wires to slave clocks meant that all the clocks in the network could be synchronized to the same precise time, making it ideal for situations where accurate timekeeping was crucial, such as in factories, offices, schools, hospitals and it was used by the B.B.C., the railway system and London underground.


The BBC’s iconic six ‘pips’ time signal originated with an idea proposed by Frank Hope-Jones
(courtesy of Synchronome Clocks)

Developments – the Shortt–Synchronome free pendulum clock


The Synchronome clock was further improved when Frank Hope-Jones collaborated with William Hamilton Shortt to create the Shortt–Synchronome free pendulum clock. Invented in 1921 it was manufactured by the Synchronome Company, Ltd.

This complex precision electromechanical clock became the most accurate pendulum clock ever commercially produced, and became the highest standard for timekeeping between the 1920s and the 1940s, after which mechanical clocks were superseded by improvements in quartz and then atomic clock time standards. These clocks were used throughout the world in observatories, scientific research, and national time dissemination services. The Shortt was the first clock to be a more accurate timekeeper than the Earth itself; it was used in 1926 to detect tiny seasonal changes in the Earth’s rotation rate. Shortt clocks achieved accuracy of around a second per year, although recent measurements have discovered they were even more accurate. About 100 were produced between 1922 and 1956.

Shortt clocks kept time with two pendulums, a primary pendulum swinging in a vacuum tank and a secondary pendulum in a separate clock, which was synchronized to the primary by electro-mechanical means. The secondary pendulum was attached to the timekeeping mechanisms of the clock, leaving the primary pendulum virtually free of external disturbances.

In 1984 Pierre Boucheron studied the accuracy of a working Shortt clock kept on display at the US Naval Observatory.  Using modern optical sensors which detected the precise time of passage of the pendulum without disturbing it, he compared its rate to an atomic clock for a month. He found that it was accurate to one second in 12 years, far more accurate than the 1 second per year that was previously measured. His data revealed the clock was so sensitive it was able to detect the slight changes in gravity due to tidal distortions in the solid Earth caused by the gravity of the Sun and Moon.

Shortt clock in US National Institute of Standards and Technology museum
(image reproduced from wikipedia)

Five facsimile pages from the Synchronome Electric Clocks catalogue

of the 1912-14 period

 from the pamphlet ‘A Hope-Jones Synchronome Miscellany‘ by F. Hope-Jones, first printed 1913-23,
and reprinted in 1995 by Tee Publishing
reproduced with thanks