Group meetings 2025

Friday 21 March 2025 at 2.00pm

VISIT: The Archive Centre IET in Savoy Place, London, to see Synchronome and Hope-Jones related papers from the Silvanus Thompson archive, and more. Finally completing a plan upset by Covid.

Booking essential.

For information email chairman@ahsoc.org

For informationon all events, contact the EHG Secretary at chairman@ahsoc.org or on 07785 296584.

Synchronome database

Synchronome master clocks are difficult to date. Although they are serial numbered, little evidence exists to tie numbers to dates. John Hubert has collated records from various sources to create a database of serial numbers, design changes and, where possible, dates of manufacture. The database is available for download here (AHS membership log-on required).

Gents C6/C7 master clock survey

Started in 2007, the Gents master clock survey has now closed (January 2019). The responses received are gratefully acknowledged, and the data supplied is currently being analysed in readiness for the preparation and publication of an updated version of Derek Bird's book “The Pulsynetic System and its Place in the History of Electric Clocks”.

Gillett & Johnston master clock
Gillett & Johnston master clock

Electrical Horology Group

Welcome to the home page of the Electrical Horology Group, a specialist group within the AHS.

The Electrical Horology Group has been in existence since 1970 and has over 150 members worldwide.

EHG members share an interest in all electrical horology, from the early beginnings in the 19th century right up to relatively modern quartz and atomic clocks. The diversity of approach in applying electrical power to winding or maintaining a clock is immense, and the ingenuity of solutions to the problems encountered is fascinating.

Meetings are held approximately four times a year, usually on a Saturday in March/April, June, September and November. A variety of venues is used; please check Antiquarian Horology or this page for the latest programme information. Meetings may involve formal lectures, short talks, visits to places of horological interest, exhibitions, visits to private collections, and so forth.

The Annual General Meeting is held in November and is often combined with a special lecture given by a guest speaker.

The Group publishes technical papers from time to time on electrical horology matters that may not have a wide enough appeal for inclusion in the Journal (see the list of published papers at the bottom of this page). These papers are available here to AHS members as part of the searchable digital archive. New papers are dependent on members providing the material for publication. Over one hundred such papers have been published so far.

Famous names in electrical horology

Personalities (listed chronologically)

Sir Francis Ronalds 1788-1873

Inventor of the Electrostatic Clock in 1814.

Alexander Bain 1811-1877

The "Father of electrical horology". He patented the first practical electromagnetically impelled clock in 1841.

Matthaus Hipp 1813-1893

Inventor of the Hipp Toggle in 1842 - a device attached to a pendulum or balance wheel that senses when the arc of swing reduces to a given point, and then closes an electrical contact to electromagnetically impel the pendulum or balance.

Frank Hope-Jones 1867-1950

Patented the best known, and arguably the most accurate, gravity impelled pendulum master clock in 1908, the Synchronome.

Henry Ellis Warren 1872-1957

Devised the first synchronous (A.C. mains powered) clock in 1918.

William Hamilton Shortt 1881–1971

Patented a highly accurate, electromagnetically impelled, free pendulum regulator clock in 1921. The clock operated in a vacuum chamber, and its accuracy was only superseded by the arrival of the Atomic clock.

Warren A. Marrison 1896–1980

Invented the quartz crystal controlled clock in 1927.

Louis Essen F.R.S. 1908-1997

Invented the Caesium Atomic clock in 1955.

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Famous Companies and Trade Names (listed alphabetically)

ATO

The company set up in France by Léon Hatot (1883-1953) made clocks under this trademark (a contraction of his own name) from 1919 . In the 1950's Hatot's company developed and patented the world's first transistorised electric clock.

Bulle

The trade name of electromagnetic pendulum clocks marketed by a company set up in France by M. Favre-Bulle. Designed in France, they were given British patents in 1922. Production continued until stopped by the Second World War, with around 300,000 units made.

Eureka

A very successful early electromagnetic clock manufactured between 1904 and 1914. The main feature was a very large balance wheel several inches in diameter. Around 10,000 clocks were made.

Gents of Leicester

A very successful company run by Messers Parsons and Ball manufacturing sturdy electrical Master Clocks from 1904 to the 1970s.

Hamilton Watch Co.

An American company which produced the first electrically maintained wrist watch in 1957, after 10 years research.

Smiths Sectric

The trade name of Smiths English Clocks Ltd in Cricklewood, London. The company produced many thousands of electric clocks, both A.C. mains powered and battery powered during the middle years of the 20th century.

Synchronome

Started in 1895, this is the company name of Frank Hope-Jones. The company produced very accurate electric Master Clocks that were capable of driving many slave clocks around a factory or office building in perfect synchronism.

Telechron

The trade mark of the Warren Clock Company in America and applied to synchronous clocks (A.C. mains powered). The name literally means "time from a distance".

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History

These are just a few of the more significant milestones in the development of electrical horology.

1840

First practical electromagnetic clock, by Alexander Bain.

1864

Distribution of time to public clocks, by Magnetic Telegraph Co, Glasgow.

1881

Electric motor to wind clock spring, by Chester H. Ponds, (USA).

1906

Eureka, first successful balance wheel electric clock, by T. B. Powers (Patented by Kutnow Bros).

1918

Synchronous electric clock invented (A.C. mains powered), by Henry Ellis Warren (USA).

1927

Quartz crystal controlled clock invented (experimental design), by Warren A. Marrison.

1931

Synclock: one of the first domestic synchronous clocks for the UK (Warren motor, A.C. mains powered), by Everett, Edgcumbe & Co.

1933

Speaking clock: the first accurate fully automatic service, Paris.

1953

Transistor first used to electronically maintain a pendulum, by Leon Hâtot (France).

1955

Caesium atomic clock, by Louis Essen.

1957

Wrist watch with electrical contacts operated directly by balance wheel produced commercially, by Hamilton Watch Co (US).

1959

Accutron watch using an electronically maintained tuning fork as timing element, by Bulova.

1970

First LED display on a wrist watch.

1971

First LCD display on a wrist watch.

1972

First mass produced domestic quartz clock, by Staiger in Germany.

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EHG Technical Papers

The Electrical Horology Group of the AHS has published a number of technical papers over the years, covering a wide range of electrical horology topics.

These papers are now available here to members of the society as part of the searchable digital archive.

The complete list of such papers shown below indicates the depth and breadth of information available to members.

Title

  1. List of articles on Electrical Horology from "Horology" and "The American Horologist & Jeweller"
  2. List of works on Electrical Horology
  3. List of works on Electrical Horology from "Practical Watch & Clockmaker
  4. List of articles on Electrical Horology from "Model Engineer"
  5. Electricity for the Antiquarian Horologist - An introduction in 5 parts
  6. A Chronoscopic Conundrum
  7. A Pendulum Electric Timepiece ca 1845 made by Alexander Bain of Edinburgh
  8. Spark Prevention
  9. The Magnetic Escapement
  10. Electric Clocks - controlling the current
  11. An Electrically Maintained Precision Pendulum Clock
  12. Magneta Master Clock - Translation from the French
  13. The Evolution of Timeswitches
  14. The "Brox" Electric Pendulum
  15. Digital Calendar Clock
  16. Electronics in Timekeeping
  17. Time Balls in and Around Charing Cross
  18. Bright's Perpetual Motion Electric Clock
  19. Quartz clocks and Atomic Time
  20. Eureka Clock Survey
  21. Rugby 60kHz Broadcast
  22. The Synchronome Master Clock - Adjustment and Setting to Work
  23. Electric Clocks Acquired by the Science Museum in 1978
  24. Breguet's Electric Clock
  25. Replacing a Bulle Clock Suspension, March 1980
  26. The Development of Batteries for Electric Clocks and Watches
  27. Electrical Horology Group - The First Ten Years
  28. The ATO Electric Clock
  29. An Early Electric Clock System
  30. The Role of Electrical Horology in the Development of the Quartz Clock
  31. Master Clock - Quartz Controlled Time Transmitter
  32. The "Chronopher" Master Clock System
  33. The Construction and Early Development of the Talking Clock
  34. A Proposal for a Time Ball at Boston, USA
  35. List of Major Electric Clock Literature available from The Franklin Institute Library, USA
  36. The "Synchronome" Astronomical Regulator>
  37. Improvements to Astronomical Clocks
  38. Stored Energy Power Supply for Synchronome Impulse Systems
  39. Adjustments to the English Clock Systems Master and Slave Clocks
  40. ITR/IBM Supervised Time System - Principle of Operation
  41. Hints for Servicing Pulsynetic Clocks
  42. Electromagnetic Clock Literature of the 19th Century
  43. Telephone Manufacturing Company Ltd. High Movement Impulse Transmitter
  44. Electric Clocks in the Science Museum Reserve Collection
  45. The Greenwich Mean Time System
  46. Time in Broadcasting
  47. The Latest Developments in Quartz Crystal Oscillators
  48. The Telephone Rentals Uniselector Chronogram
  49. The Electric Clock Systems of the London Underground
  50. An Earth Cell Experiment
  51. National Time Standards
  52. Almost Perpetual Motion - The Amazing Clinker Pendulum Clock
  53. 100 Years of the Domestic Electric Clock
  54. (The Bulle Clock - Practical Manual) Available as a book from the AHS
  55. The Fedchenko Isochronous Pendulum Suspension Spring
  56. Catalogue of Exhibition of Electrical Clocks Working on the Hipp Toggle Principle
  57. Matthaus Hipp of Reutlingen
  58. Smiths - An Overview of Their Activities in Electrical Horology
  59. Warren's Synchronous Clocks
  60. Ffolliott Gray's Invention "The Duo Electric Clock"
  61. Siemens & Halske Electric Clocks 1847-1945
  62. Post Office Clock Survey
  63. "Clocks Magazine" - Electrical Horology Index
  64. Gillett & Johnston Master Electric Clock - Setting up and servicing
  65. Rabe Bros. of Hanau - Torsion Pendulum Clocks
  66. The Beginning of the Liquid Crystal Watch
  67. Pul-Syn-Etic clocks, Installation, Maintenance and Repair (Revised)
    67. Pul-Syn-Etic Clocks, Supplement 1
    67. Pul-Syn-Etic Clocks, Supplement 2
  68. English Clock Systems Ltd 1-Second Master Clock
  69. Gent Fig.C53 Strike Controller
  70. 100 Years of Paul Schroder of Stuttgart 1902-2002
  71. The Quartz Revolution
  72. Master Clocks Designed & Manufactured By Gent Ltd - 1898 to 1980
  73. A Celebration of the Centenary of the Eureka Clock Patent
  74. The Lowne Electric Clock Company - History & Servicing the Master Clocks
  75. Servicing Procedures & Catalogue Details for the TMC 'SPB' Half Second Master Clock
  76. Bulle: A Study into the Effectiveness of the Isochronous Spring.
  77. An Approximate Expression for the Effect of the Bulle Isochronal Spring
  78. Frank Holden – the Man and his Clocks
  79. P A Bentley - The Man and his Clocks
  80. Recollections of 40 years of the Electrical Horology Group
  81. A Game of Numbers - some observation on serial numbers
  82. English Clock Systems Ltd - Revisited
  83. Telephone Rentals and their activities in electric clocks
  84. Battery Insertion Movements DVD
  85. Searching Patents
  86. Stanley John Wise - The Author and His Electric Clocks
  87. An earth cell investigation
  88. Index of electrcal items in Clocks Magazine - Paper No 63 update
  89. Tayco clocks
  90. The ‘Wallace and Tiernan’ Electric Clock
  91. The Forestville ‘Eureka’ Electric Clock
  92. Gent DAC Chronometer
  93. Gent Survey - The Results
  94. Vitascope clocks
  95. ITR Electronic Master Clocks Models M23, M24 & M27
  96. Murday survey
  97. Schonberg
  98. Post Office Hipp Toggle clock systems
  99. Ateliers Vaucanson
  100. Ansonia Electric Wind
  101. Burk Puja Handley

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