Course Outline

Since ancient times people have developed ever more accurate clocks and timekeeping devices. What are these and how do they work? Why do we need increasingly accurate timekeeping? How has increasingly accurate timekeeping affected our daily lives?

This course aims to explore the history and development of timekeeping. Part of the course material will cover basic ideas about the workings of these devices and the physics and science involved. This will include assessing the type of accuracy needed to use timekeeping devices to accomplish tasks effectively. The course material will also describe the context behind timekeeping. This includes perhaps unexpected diversity of contexts such as the arranging the day in medieval monasteries, early industrial activity in Europe during the Middle Ages, trans-Atlantic navigation, railroads in the 19th century and modern GPS.

The course will cover the following topics subject to minor modifications.

  1. Astronomical timekeeping.
  2. Timekeeping in ancient and medieval times: sundials and water clocks.
  3. Mechanical clocks.
  4. Clocks and navigation.
  5. Standardizing time.
  6. Electronic clocks.
  7. Atomic clocks.
  8. Demands for and uses of precision timekeeping in society.

Homework Assignments

Due: 30 August 2021 Homework 1
Due: 6 September 2021 Homework 2
Due: 13 September 2021 Homework 3
Due: 22 September 2021 Homework 4
Due: 18 October 2021 Homework 5
Due: 8 November 2021 Homework 6
Due: 15 November 2021 Homework 7
Due: 3 December 2021 Homework 8

Papers

There will be two short papers due on the following dates: Friday 1 October 2021 and Wednesday 27 October 2021. There will a term paper whose first draft is due on Monday 29 November 2021 and whose final draft is due on Friday 10 December 2021.

Supplementary Reading: Texts

Texts about time, clocks and timekeeping span a wide variety of topics and styles. Many of these are available in CMU's Tomlinson Library.

  1. General Timekeeping: History and Society

    1. J. E. Barnett, Time's Pendulum, Harcourt (1998).

      Good overview of the history of timekeeping written for a general audience. The latter part of the text is an extensive overview of geological timescales.

    2. D. S. Landes, Revolution in Time, Harvard University Press (1983).

      Detailed description of the history of timekeeping. Written in an academic history style. Requires some knowledge of various historical eras, particularly in Europe. Detailed coverage of the watch making industry in Europe, the US and Japan.

    3. G. Dohrn-van Rossum, History of the Hour, University of Chicago Press (1996).

      In-depth coverage of the history of timekeeping with a strong focus on the Middle Ages and Renaissance. Mostly focuses on the social history of timekeeping. Extensive list of references.

    4. C. M. Cippola, Clocks and Culture, Norton (1978).

      Readable coverage of the history of timekeeping during the Middle Ages and Renaissance. Too bad it stops at 1700!

    5. G. J. Whitrow, Time in History: Views of Time from Prehistory to the Present Day, Barnes and Noble (2004).

      General history of timekeeping. Very readable.

    6. D. Howse, Greenwich Time and the Longitude, Philip Wilson (1997).

      Nicely illustrated history of the development of the Greenwich observatory and its role in timekeeping and longitude. Accessible descriptions of the basic technicalities of astronomical timekeeping techniques.

    7. R. de Grijs, Time And Time Again: Determination Of Longitude At Sea In The 17th Century, IOP Publishing (2017).

    8. R. T. Gould, The Marine Chronometer: Its History and Development, Antique Collectors' Club (1989).

      Details about the clocks used to determine longitude.

    9. D. Sobel, Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of his Time, Walker (1995).

      The story of John Harrison and his marine chronometers.

    10. M. O'Malley, Keeping watch: A History of American Time, Viking (1990).

      Detailed history of timekeeping in the US. Includes time standardization, time zones.

    11. I. R. Bartky, Selling the True Time: Nineteenth-Century Timekeeping in America, Stanford (2000).

      Detailed description of the political and economic developments that led to time standardization in the US. Long list of references including many original sources.

    12. M. C. Harrold, American Watchmaking: A Technical History of the American Watch Industry, 1850-1930, NAWCC (2017).

      Detailed history of watchmaking industry in the US.

  2. Technology of Timekeeping

    1. R. Du and L. Xie, The Mechanics of Mechanical Watches and Clocks, Springer (2013).

      Details about the mechanical workings of clocks. Nice schematic diagrams and other illustrations.

    2. D. D. McCarthy and P. K. Seidelmann, Time: From Earth Rotation to Atomic Physics, Cambridge University Press (2018).

      Detailed technical descriptions of how time is measured and how we arrive at universal timescales, definitions of the second and how electronic and atomic clocks work. Technical and requires some physics and mathematics.

    3. J. Jespersen and J. Fitz-Randolph, From Sundials to Atomic Clocks: Understanding Time and Frequency, Dover (1999).

      A reprint of a NIST monograph intended to describe the technology of timekeeping to a general audience. Uses cartoons, colloquial explanations and easily understood language. The ultimate aim seems to be to describe the timekeeping work done at NIST to a general audience. Available from NIST here and here (pdf).

    4. A. E. Waugh, Sundials: Their Theory and Construction, Dover (1973).

      Tremendous details about the construction and calibration of many types of sundials.

  3. Timekeeping and Physics

    1. C. A. Pickover, Time: A Traveller's Guide, Oxford University Press (1998).

      The physics of time from a relativity perspective. Time and space in physics are connected in very counter-intuitive ways. Will require the ability to digest basic physics.

  4. Time and People

    1. K. K. Birth, Objects of Time, Palgrave Macmillan (2012).

      How we understand time from the perspective of psychology and culture.

Supplementary Reading: Journal Articles

Journal articles and monographs about time, clocks and timekeeping.

  1. General
    1. Compendium of publicly available articles produced by the National Institute of Standards and Time (NIST). The articles can be looked up at the NIST Time and Frequency Publication Database.
    2. Time and Society A journal devoted to this subject.
    3. Vistas in Astronomy, Vol 28 Part 1 An entire edition commemorating the 1884 International Meridian Conference and devoted to longitude and timekeeping.
    4. Andrewes, W. J. H., A Chronicle Of Timekeeping, Scientific American, Vol. 287, No. 3, pp. 76-85 (2002).
  2. Sundials, Water Clocks and Other Early Timekeeping Devices
    1. Armstrong J. E. and Camp J. McK., Notes on a Water Clock in the Athenian Agora, Hesperia, Vol. 46, No. 2, pp. 147-161 (1977).
    2. Balmer R. T., The Operation of Sand Clocks and Their Medieval Development, Technology and Culture, Vol. 19, No. 4, pp. 615-632 (1978).
    3. Balmer R. T., The Invention of the Sand Clock, Endeavour, Vol. 3, No. 3, pp. 118-122 (1979).
    4. Berggren J. L., Sundials in Medieval Islamic Science and Civilization, The Compendium, Vol. 8, No. 2, pp. 8 - 14 (2001).
    5. Charette, F., High tech from Ancient Greece, Nature, Vol. 444, pp. 551 - 552 (2006).
    6. B. Cotterell, F.P. Dickson, J. Kamminga, Ancient Egyptian water-clocks: A reappraisal, Journal of Archaeological Science, Vol. 13, No. 1, pp. 31 - 50 (1986).
    7. de Solla Price, D. J., Automata and the Origins of Mechanism and Mechanistic Philosophy, Technology and Culture, Vol. 5, No. 1, pp. 9-23 (1964).
    8. Drachmann, A.G., Ktesibios's Waterclock and Heron's Adjustable Siphon, Centaurus, Vol. 20, No. 1, pp. 1-10 (1976).
    9. Farre-Olive, A medieval Catalan clepsydra and carillon, Antiquarian Horology, Vol. 18, No. 4, pp. 371-380 (1989).
    10. Fermor J. H, Burgess A. B., Przybylinski, V. The timekeeping of Egyptian outflow clocks, Endeavour, Vol. 7, Issue 3, pp 133-136 (1979).
    11. Field, J.V. and Wright M.T., Gears from the Byzantines: A portable sundial with calendrical gearing, Annals of Science, Vol 42, No. 2, 87-138 (1985).
    12. Glick, T. F., Medieval Irrigation Clocks, Technology and Culture, Vol. 10, No. 3, pp. 424-428 (1969).
    13. Hannah, R., Time-Telling Devices, Ch. 55 in A Companion To Science, Technology, And Medicine In Ancient Greece And Rome, Ed. Irby, G. I. (2016).
    14. Hwang, Z.-H. and Yan, H.-S. and Lin, T.-Y., Historical development of water-powered mechanical clocks, Mechanical Sciences, Vol. 12, Issue 1, pp 203-219 (2021).
    15. Landels. J. G., Water-clocks and time measurement in classical antiquity, Endeavour, Vol. 7, Issue 1, pp 32 -37 (1979).
    16. Noble, J. V. and de Solla Price, D, J., The Water Clock in the Tower of the Winds, American Journal of Archaeology, Vol. 72, No. 4, pp. 345-355 (1968).
    17. Sloley, R. W., Primitive Methods of Measuring Time: With Special Reference to Egypt, J. Egyptian Archaeology, Vol. 17, No. 3/4, pp. 166-178 (1931).
    18. Sonderegger, H., History of Portable Sundials, The Compendium, Journal of NASS, Vol. 27, No. 1, pp. 19-35 (March 2020).
    19. Turner A. J., Sun-Dials: History and Classification, History of Science, Vol 27, No. 3, pp 303-318 (1989).
    20. Wright M. T., Greek and Roman Portable Sundials: An Ancient Essay in Approximation, Archive for History of Exact Sciences, Vol. 55, No. 2, pp. 157- 187 (2000).
    21. Young, S., An Athenian Clepsydra, Hesperia, Vol. 8, No. 3, The American Excavations in the Athenian Agora: Sixteenth Report, pp. 274-284 (1939).
  3. Early Mechanical Clocks and Medieval Timekeeping
    1. Andrewes, W. J. H., Time For The Astronomer 1484-1884, Vistas in Astronomy, Vol. 28, Part 1, pp 69-86 (1985).
    2. Bradbury, N. M., and Collette, C. P., Changing Times: The Mechanical Clock In Late Medieval Literature, The Chaucer Review , 2009, Vol. 43, No. 4, Time, Measure, and Value in Chaucer's Art and Chaucer's World, pp. 351-375 (2009).
    3. Boerner, L., Rubin, J., Severgnini, B., A Time To Print, A Time To Reform, European Economic Review, Vol. 138, 103826 (2021).
    4. Epstein, S., Business Cycles And The Sense Of Time In Medieval Genoa, Business History Review, Vol. 62 Issue 2, pp 238-260 (1988).
    5. Farre-Olive, E. 1.000 Años De Relojería Catalana, Collectors No. 3/11, pp 40 - 45 (1988) (In Spanish).
    6. Garceau, M. E.. 'I call the people.' Church bells in fourteenth-century Catalunya, Vol 37, No. 2, pp 197 -214 (2011).
    7. Le Goff J., Church time and merchant time in the Middle Ages, Social Science Information, Volume 9, No. 4, pp. 151-167 (1970).
    8. Linnard, W., Robey, J. A., Wright, M. T., Ung petit traictie pour faire horoleiges: A little treatise for making clocks in the fourteenth century, Antiquarian Horology, Volume 37, No. 2, pp. 182-198 (2016).
    9. Maccagni, C., The Florentine Clock- And Instrument-Makers Of The Della Volpaia Family, Der Globusfreund, Issue 18-20, pp 92 - 99 (1970).
    10. North J. D., Monasticism and the First Mechanical Clocks, In: Fraser J.T., Lawrence N. (eds) The Study of Time II. Springer, Berlin, Heidelberg (1975).
    11. Perez, V., The role of the mechanical clock in medieval science, Endeavour, Vol. 39, Issue 1, pp 63-68 (2015).
    12. Pihko, S., Chapter 2 Temporal Expressions in Canonisation Processes and Diari, and the Perception of Time in Late Medieval Rome, In Time in the Eternal City. Leiden, The Netherlands (2020).
    13. Scattergood, J., Writing the clock: The reconstruction of time in the late Middle Ages, European Review, Vol. 11, No. 4, pp. 453-474 (2003).
    14. Thorndike, L., Invention of the Mechanical Clock about 1271 A.D., Speculum, Vol. 16, No. 2, pp. 242-243 (1941).
    15. Turner, A., The Eclipse of the Sun: Sun-dials, Clocks and Natural Time in the Late Seventeenth Century, Early Science and Medicine, Vol. 20, No. 2, pp. 169-186 (2015).
    16. Wilkin, A., Time constraints on market activity and the balance of power in medieval Liege, Continuity and Change, Vol. 30, No. 3, 315-340 (2015).
    17. Zerubavel, E., The Benedictine Ethic and the Modern Spirit of Scheduling: on Schedules and Social Organization, Sociological Inquiry, Vol. 50, pp 157 - 169 (1980).
  4. Pendulum and Balance Spring Clocks
    1. Matthew Bennett, Michael F. Schatz, Heidi Rockwood and Kurt Wiesenfeld, Huygens's Clocks, Proceedings: Mathematical, Physical and Engineering Sciences, Vol. 458, No. 2019, pp. 563-579 (2002).
    2. Hall A.R., Robert Hooke and Horology, Notes Rec. R. Soc. Lond., Vol 8 pp167-177 (1951).
    3. Howard, N., Marketing Longitude: Clocks, Kings, Courtiers, and Christiaan Huygens, Book History, Vol. 11, pp. 59-88 (2008).
    4. McEvoy, R., Introducing The Precision Pendulum Clock, in Harrison Decoded: Towards A Perfect Pendulum Clock, eds. R. McEvoy and J. Betts, Oxford University Press (2020).
    5. Louise Diehl Patterson, Pendulums of Wren and Hooke, Osiris, Vol. 10, pp. 277-321 (1952).
    6. Plomp, R., A Longitude Timekeeper by Isaac Thuret with the Balance Spring Invented by Christiaan Huygens, Annals Of Science, Vol. 56 , pp379-394 (1999).
    7. Alfons Van Der Kraan, The Dutch East India Company, Christiaan Huygens and the Marine Clock, 1682-95, Prometheus, Vol. 19, No. 4, (2001).
    8. Whitestone, S., Christian Huygens' Lost and Forgotten Pamphlet of his Pendulum Invention, Annals Of Science, Vol. 69, No. 1, 91-104 (2012).
  5. Longitude and Chronometers
    1. Aguirre E. L., Greenwich: Center of Space and Time, Sky and Telescope, August 2005, p99-103 (2005).
    2. Betts, J., John Harrison: Inventor Of The Precision Timekeeper, Endeavour, Vol. 17, Issue 4, p160-167 (1993).
    3. Buisseret, D., Charles Boucher of Jamaica and the Establishment of Greenwich Longitude, Imago Mundi, Vol. 62, No. 2, pp. 239-247 (2010).
    4. Davies, A. C., The Life and Death of a Scientific Instrument: the Marine Chronometer, 1770-1920, Annals of Science, Vol. 35, Issue 5, p509 (1978).
    5. de Grijs R., A (Not So) Brief History Of Lunar Distances: Lunar Longitude Determination At Sea Before The Chronometer, Journal of Astronomical History and Heritage, Vol 23, No 3, 495-522 (2020).
    6. de Grijs R., European Longitude Prizes.I: Longitude Determination In The Spanish Empire, Journal of Astronomical History and Heritage, Vol 23, No 3, 465-494 (2020).
    7. de Grijs R., European Longitude Prizes. 2: Astronomy, Religion And Engineering Solutions In The Dutch Republic, Journal of Astronomical History and Heritage, Vol 24, No 2, 405-439 (2021).
    8. de Grijs R., European Longitude Prizes. 3: The Unsolved Mystery Of An Alleged Venetian Longitude Prize, Journal of Astronomical History and Heritage, Vol 24, No 3, 728?738 (2021).
    9. de Grijs R., European Longitude Prizes. 4: Thomas Axe's Impossible Terms Journal of Astronomical History and Heritage, Vol 24, No 3, 739-750 (2021).
    10. Edwards C. R., Mapping by Questionnaire: An Early Spanish Attempt to Determine New World Geographical Positions, Imago Mundi, Vol. 23, pp. 17-28 (1969).
    11. Forbes, E. G., The origins of the Greenwich observatory, Vistas in Astronomy, Vol. 20, Part 1, pp 39-50 (1976).
    12. May, W. F., and Howse H. D., How The Chronometer Went To Sea, Vistas in Astronomy, Vol. 20, pp. 135-137 (1976).
    13. Proverbio E., The Contribution Of The Mechanical Clock To The Improvement Of Navigation, Vistas in Astronomy, Vol. 28, pp. 95-103 (1985).
    14. Randles, W. G. L., Portuguese and Spanish attempts to measure longitude in the 16th century, Vistas in Astronomy, Vol. 28, pp 235-241 (1985).
    15. Smith H. M., Greenwich time and the prime meridian, Vistas in Astronomy, Vol. 20, pp 219-229 (1976).
    16. Turner, A. J., France, Britain And The Resolution Of The Longitude Problem In The 18th Century, Vistas in Astronomy, Vol. 28, pp 315-319 (1985).
    17. Waldo, L., On the Longitude of Waltham, Mass., Proceedings of the American Academy of Arts and Sciences, Vol. 13, pp. 175-182 (1878).
    18. Withers C. W. J., The Longitude Question, Journal of Historical Geography, Vol. 47, pp. 1-5 (2015).
    19. Wright, J. K., Notes on the Knowledge of Latitudes and Longitudes in the Middle Ages, Isis Vol. 5, No. 1, pp. 75-98 (1923).
  6. Watchmaking and the Watch Industry
    1. Richard Watkins Horological Books, Translations of many watchmaking articles can be found here.
    2. Aguillaume, C., The Swiss Watchmaking Industry Faced With Globalisation In The 1970s, Icon, Vol. 12, pp. 190-217 (2006).
    3. Carosso V. P., The Waltham Watch Company: A Case History, Bulletin of the Business Historical Society, Vol. 23, No. 4, pp. 165-187 (1949).
    4. Church, R. A., Nineteenth-Century Clock Technology in Britain, the United States, and Switzerland, The Economic History Review , Vol. 28, No. 4, pp. 616-630 (1975).
    5. Davies, A. C., Rural Clockmaking in Eighteenth-Century Wales: Samuel Roberts of Llanfair Caereinion, 1755-1774, The Business History Review, Vol. 59, No. 1, pp. 49-75 (1985).
    6. Davies, A. C., British Watchmaking and the American System, Business History, Vol. 35, Issue 1, p40. (1993).
    7. Donze, P., Le Japon et l'industrie horlogere suisse. Un cas de transfert de technologie durant les annees 1880-1940, Histoire, Economie et Societe, Vol. 25, No. 4, pp. 105-125 (2006).
    8. Donze, P., Global Value Chains And The Lost Competitiveness Of The Japanese Watch Industry: An Applied Business History Of Seiko Since 1990, Asia Pacific Business Review, Vol. 21, No. 3, 295-310 (2015).
    9. Donze, P., The Transformation Of Global Luxury Brands: The Case Of The Swiss Watch Company Longines, 1880-2010, Business History, Vol. 62, Issue 1, pp 26-41 (2020).
    10. Kebir, L. and Crevoisier, O.,Cultural Resources and Regional Development: The Case of the Cultural Legacy of Watchmaking, European Planning Studies, Vol. 16, Issue 9, pp 1189-1205 (2008).
    11. Lamard, P.,Worldwide Phenomenon And Transfers Of Technology: Swiss And French Watch Making In The Face Of The Centennial Exhibition Of Philadelphia (1876), Icon , 2002, Vol. 8, pp. 33-42 (2002).
    12. Landes, D. S.,Watchmaking: A Case Study in Enterprise and Change, The Business History Review, Vol. 53, No. 1, pp. 1-39 (1979).
    13. Sinclair, M, Connoisseurship as a Substitute for User Research? The Case of the Swiss Watch Industry, Journal of Research Practice, Volume 11, Issue 2, Article M11, (2015).
    14. Waldo, L., The Mechanical Art of American Watchmaking, The Journal of the Society of Arts, Vol. 34, No. 1748, pp. 739-758 (1886).
  7. Time Discipline and Consciousness
    1. Allen, D. S., The Flux of Time in Ancient Greece, Daedalus, Vol. 132, No. 2, pp. 62-73 (2003).
    2. Epstein, S. A., Business Cycles and the Sense of Time in Medieval Genoa, The Business History Review, Vol. 62, No. 2, pp. 238-260 (1988).
    3. Harrison, M.,The Ordering of the Urban Environment: Time, Work and the Occurrence of Crowds 1790-1835, Past & Present, No. 110, pp. 134-168 (1986).
    4. Landes D. S., The Ordering of the Urban Environment: Time, Work and the Occurrence of Crowds 1790-1835, Past & Present, No. 116, pp. 192-199 (1987).
    5. Landes D. S., Clocks & the Wealth of Nations, Daedalus, Vol. 132, No. 2, pp. 20-26 (2003).
    6. McCrossen A., The "Very Delicate Construction" of Pocket Watches and Time Consciousness in the Nineteenth Century United States, Winterthur Portfolio, Vol. 44, No. 1, pp. 1-30 (2010).
    7. Steele, I. K., Time, Communications and Society: The English Atlantic, 1702, Journal of American Studies, Vol. 8, No. 1, pp. 1-21 (1974).
    8. Thompson, E. P., Time, Work-Discipline, and Industrial Capitalism, Past & Present, No. 38, pp. 56-97 (1967).
  8. Standardization of Time
    1. Bartky, I., The Invention of Railroad Time, Railroad History, No. 148, pp. 13-22 (1983).
    2. Bartky, I., A Comment on "The Standardization of Time" By Zerubavel, American Journal of Sociology, Vol. 89, No. 6, pp. 1420-1425 (1984).
    3. Bartky, I., Inventing, introducing and objecting to standard time, Vistas in Astronomy, Vol. 28, Part 1, pp 105-111 (1985).
    4. Bartky, I., Running on Time, Railroad History, No. 159, pp. 18-38 (1989).
    5. Bartky, I., The Adoption of Standard Time, Technology and Culture, Vol. 30, No. 1, pp. 25-56 (1989).
    6. Bartky, I. and Dick, S. J., The First North American Time Ball, Journal for the History of Astronomy, Vol 13, No. 1, pp. 50-54 (1982).
    7. Bartky, I. and Harrison, E., Standard and Daylight-saving Time, Scientific American , Vol. 240, No. 5, pp. 46-53 (1979).
    8. Bartky, I. and Stephens C. E., Comment and Response on "The Most Reliable Time," Technology and Culture, Vol. 32, No. 1, pp. 183-186 (1991).
    9. Corliss, C. J.,The Day of Two Noons, 6ed, Association of American Railroads (1952).
    10. Creet, M., Sandford Fleming and Universal Time,Scientia Canadensis, Vol. 14, Issue 1-2, pp. 66-89 (1990).
    11. Dick, S. J., The First Time Balls and the First North American Time Ball, In: Space, Time, and Aliens. Springer (2020).
    12. Edney, M. H., Cartographic Culture and Nationalism in the Early United States: Benjamin Vaughan and the Choice for a Prime Meridian, 1811, Journal of Historical Geography, Vol 20, No. 4, pp 384-395 (1994).
    13. Gay, H., Clock Synchrony, Time Distribution and Electrical Timekeeping in Britain 1880-1925, Past & Present, No. 181, pp. 107-140 (2003).
    14. Higgitt, R., and Dolan, G., Greenwich, time and 'the line', Endeavour, Vol.34 Issue 1, pp. 35-39 (2010).
    15. Howse, D., 1884 And Longitude Zero, Vistas in Astronomy, Vol. 28, pp. 11-19 (1985).
    16. Ishibashi, Y., In Pursuit of Accurate Timekeeping: Liverpool and Victorian Electrical Horology, Annals Of Science, Vol. 71, No. 4, 474-496 (2014).
    17. Krupp, E. C., Priming the Meridian, Sky and Telescope, January 2008, pp 51-52 (2008).
    18. Perrin, W. G., The Prime Meridian, Mariner's Mirror, April 1927 (1927).
    19. Rooney D., and Nye J., 'Greenwich Observatory Time for the Public Benefit': Standard Time and Victorian Networks of Regulation, The British Journal for the History of Science, Vol. 42, No. 1, pp. 5-30 (2009).
    20. Smith, H. M., Greenwich Time and the Prime Meridian, Vistas in Astronomy, Vol. 20, pp. 219-229 (1976).
    21. Smith, H. S. S., Standard Time, Transactions of the Annual Meetings of the Kansas Academy of Science, Vol. 8, pp. 30-32 (1882).
    22. Stephens, C., "The Most Reliable Time": William Bond, the New England Railroads, and Time Awareness in 19th-Century America, Technology and Culture, Vol. 30, No. 1, pp. 1-24 (1989).
    23. Stephens, C., Before Standard Time: Distributing Time In 19th-Century America, Vistas in Astronomy, Vol. 28, pp. 113-118 (1985).
    24. Stephens, C., The impact of the telegraph on public time in the United States, 1844-93, IEEE Technology and Society Magazine, Vol. 8, Issue 1, pp 4 -10 (1990).
    25. Waldo, L., The Distribution of Time, Science, Vol. 1, No. 23, pp. 277-280 (1880).
    26. Waldo, L., Railroad and Public Time, The North American Review, Vol. 137, No. 325, pp. 605- 609 (1883).
    27. Waltham Observatory, Standard Time at a Modern Watch Factory, Scientific American , Vol. 92, No. 15, pp. 300-301 (1905).
    28. Young, C. A., Standard Time, Science, Vol. 3, No. 81, pp. 15-16 (1882).
    29. Zerubavel, E., The Standardization of Time: A Sociohistorical Perspective, American Journal of Sociology, Vol. 88, No. 1, pp. 1-23 (1982).
  9. Quartz and Electronic Clocks
    1. Katzir, S., Pursuing frequency standards and control:the invention of quartz clock technologies, Annals of Science, Vol. 73, No. 1, pp 1 - 39 (2016).
    2. Katzir, S., Variations and Combinations: Invention and Development of Quartz Clock Technologies at AT&T, Icon, Vol. 22, pp. 78-114 (2016).
    3. Katzir, S., Time Standards for the Twentieth Century: Telecommunication, Physics, and the Quartz Clock, The Journal of Modern History, Vol. 89, pp 119-150 (2017).
    4. Lombardi, M. A., The Accuracy and Stability of Quartz Watches, Horological Journal, February 2008, pp 57 - 59 (2008).
    5. Lombardi, M. A., The Evolution of Time Measurement, Part 2: Quartz Clocks, IEEE Instrumentation & Measurement Magazine, October 2011, pp 41 - 48 (2011).
    6. Stephens, C. and Dennis, M., Engineering Time: Inventing the Electronic Wristwatch, The British Journal for the History of Science, Vol. 33, No. 4, pp. 477-497 (2000).
  10. Atomic Clocks
    1. Lombardi, M. A., and Nelson, G.K., WWVB: A Half Century of Delivering Accurate Frequency and Time by Radio, Journal of Research of the National Institute of Standards and Technology, Vol. 119, pp 25 - 54 (2014).
    2. Lombardi, M. A., Novick, A.N., Neville-Neil G., and Cooke, B., Accurate, Traceable, and Verifiable Time Synchronization for World Financial Markets, Journal of Research of the National Institute of Standards and Technology, Vol. 121, pp 436 - 463 (2016).
    3. Jeff A. Sherman and Judah Levine, Usage Analysis of the NIST Internet Time Service, Journal of Research of the National Institute of Standards and Technology, Vol. 121, pp 33 - 46 (2016).
    4. Smith, H.M., International Coordination And Atomic Time, Vistas in Astronomy, Vol 28, pp. 123-128 (1985).

Links and Animations

  1. Timekeeping
    1. A Walk Through Time - The Evolution of Time Measurement Through the Ages. From the National Institute of Standards and Time (NIST).
    2. The Physics of Time Keeping. From Justin Cannon, University of Alaska, Fairbanks.
    3. Clock and Watch History. From History of Watch.
    4. Time and Navigation. From the Smithsonian Museum.
    5. On Time. From the National Museum of American History
    6. Second. Website about the definition of the second. From NIST.
    7. Find out more about the watch industry. From the Federation of the Swiss Watch Industry.
    8. Timepiece Knowledge. From the Seiko Museum.
  2. Examples of Precision Timekeeping
    1. Close Finishes in the 2018 Winter Olympics. From NBC Sports.
    2. Close Finishes in Bobsleigh Races. From IBSF Bobsleigh and Skeleton.
    3. Million Dollar Microsecond. From RadioLab, 4 Feb 2013.
  3. Astronomical Methods of Keeping Time
    1. Earth's Motion. YouTube video from LittleOrisek1.
    2. Motions of the Sun Simulator. From ??.
    3. Motions of the Sun Lab. From University of Nebraska.
    4. Rotating Sky Lab. From University of Nebraska.
  4. Sundials
    1. Sundial Animation. From Daniel Douch, Wanganui Park Secondary College.
    2. Time Lapse Sundial. Video by NatureClip.
    3. Sundial Animated. Animation of a portable sundial. From History of Science Museum, University of Oxford.
    4. Diptych Sundial Animated. Video of a portable sundial. From History of Science Museum, University of Oxford.
    5. Animated Shadows on Virtual Stone. From New York University.
    6. The British Sundial Society. Many descriptions of how sundials work plus their history.
    7. Short History of Sundials. From EAAE.
    8. History of Sundials. From Border Sundials.
    9. The Virtual Dial. Very detailed animation. From Queens' College, Cambridge.
    10. Sine Sole Sileo Sundial. Apparently accurate to 10s.
    11. Inglesides Terraces Sundial. From SFOG.
    12. Jantar Mantar Images. From Wikimedia.
  5. Water Clocks
    1. Clepsydra at the Ancient Agora Museum, Athens. From Wikimedia.
    2. Clepsydra of Ctesibius. From Marty Jopson.
    3. Water Clock From me3340.
    4. Ancient Mechanical Clocks. From electrostatic.
    5. Homemade Clepsydra. From Ian McInnes.
    6. Water Clock Animation. From the History of Physics website.
    7. Water Clock History. From Daniel Mintz, University of St. Andrews.
    8. Outflow Water Clock in the Agora of Athens. Wikimedia.
    9. Tower of the Winds. Wikipedia.
    10. Royal Gorge Water Clock. Apparently the only water clock of this type in Colorado.
    11. Gishodo Watch Clock Museum. Features a replica of Su Song's clock. In Nagano prefecture, Japan.
    12. Archimedes' Water Clock. Features a replica of Archimedes' clock. Kotsanas Museum, Greece.
    13. List of Ingenious Mechanical Devices. List of Al Jazari's medieval water clocks.
    14. Clocks from Medieval Muslim Civilization. From Muslim Heritage Museum.
    15. Harun al Rashid's Clock. From Muslim Heritage Museum.
    16. Al Jazari's Elephant Clock. From Muslim Heritage Museum.
    17. Al Jazari's Peacock Clock. From Muslim Heritage Museum.
    18. Al Jazari's Castle Water Clock. From Muslim Heritage Museum.
    19. Bible Moralisee Water Clock Illustration. From Art HIstory Public Initiative.
  6. Early Mechanical Devices
    1. Antikythera Mechanism. Wikipedia article.
  7. Verge and Foliot Clocks
    1. Wooden Verge and Foliot Clock. Constructed by Brain Law.
    2. Medieval Verge and Foliot Clock. Reconstruction of a Danish medieval clock. Video from Collin Gribbons.
    3. Verge and Foliot Animation. By Ken Kuo.
    4. Salisbury Cathedral Clock. YouTube video.
    5. Salisbury Cathedral Clock. Nice explanation of clockwork. YouTube video from Salisbury Cathedral.
    6. Medieval Illustration of a Clock. From Horologium aeternae sapientiae, Heinrich Seuse, at Royal Library, Brussels.
    7. Chioggia Clock Tower. Italy. From ArteChioggia.
    8. Weight-Driven Wall Clock. Verge and balance wheel. Made by William Bowyer about 1625-1635. British Museum.
  8. Early Planetary Clocks and Astraria
    1. Dondi's Astrarium. From Cabinet, University of Oxford.
    2. Replica of Dondi's Astrarium. From Museo Nazionale Scienza e Tecnologia Leonardo da Vinci, Milan.
    3. Wallingford and Clock. Manuscript illustrating Richard Wallingford and a clock. From the British Library.
    4. Wallingford Clock Escapement. Video of a replica at the Whipple Museum, Cambridge.
    5. Wallingford Clock Striking Mechanism. Video of a replica at the Whipple Museum, Cambridge.
    6. Wells Cathedral Clock. Wikipedia page.
    7. Prague Astronomical Clock. Wikipedia page with details about appearance and how it works.
    8. Astronomical Clock of Strasbourg. Video showing operation of a more modern reconstruction.
    9. Coq Automate. Oldest extant piece of an automata, Musée des Arts Décoratifs, Strasbourg.
    10. L'Horlogerie. Oldest extant piece of an automata, Musée des Arts Décoratifs, Strasbourg.
  9. Medieval Timekeeping
    1. Heinrich Suzo: De Scientia. Manuscript (MS IV III) Bibliothèque Royale de Belgique, Brussels. Illustrates various medieval clocks.
    2. Predis, Cristoforo de: De Sphaera Manuscript (Ms. lat. 209), Biblioteca Estense, Modena. Illustrates medieval clockmakers.
    3. School scene. From a Pentateuch written in 1395, British Library, MS 19776, f72v.
    4. Mechanical Clock. From a 1450 document, Bodleian Library MS. Laud Misc. 570.
    5. Miniature with a wall clock. From La Fleur des histoires, de Jean Mansel, Bibliothèque National de France, MS 5087, folio 221v.
  10. Spring Clocks
    1. How a Watch Works. YouTube video showing a mainspring watch.
    2. How a Watch Works 1949. Video from Hamilton Watch Company.
    3. Consider The Mainspring. Detailed description of mainspring construction from Hodinkee.
    4. Fusee clock unwinding. From James Swift.
    5. Fusee and chain operation. From Zenith.
    6. The Burgundy Clock. Dates to 1435. From the German National Museum.
    7. Henlein Clock. Dates to 1530/1580. From the German National Museum.
    8. Henlein Clock Animation 1. Part 1, from the German National Museum.
    9. Henlein Clock Animation 2. Part 2, from the German National Museum.
    10. Table Clock. Dates to mid 1500s. From the Metropolitan Museum.
    11. Spring-Driven Table Clock. Verge and balance wheel. Made in Augsburg 1595 - 1605. British Museum.
  11. Pendulum Clocks
    1. Galileo's Pendulum Clock. Design and replica from the Science Museum.
    2. Huygens' Pendulum Clock. History from APS Physics.
    3. Huygens' Pendulum Clock. Wikimedia image.
    4. Replica Huygens' Pendulum Clock. YouTube video by Jacques Favre.
    5. How Tower Clocks Work. YouTube video from Trevor Murphy.
    6. Tower Clock: Anchor Escapement and Pendulum. YouTube video from Trevor Murphy.
    7. Lantern Clock. Made by James Markwick about 1665 - 1675. British Museum.
    8. Traveling Clock. Made by Daniel Quare about 1685 - 1695. British Museum.
    9. Wall Bracket Clock. Made by Giovanni Baptista de Albertis 1685. British Museum.
    10. Lantern Clock. Made by Thomas Tompion about 1705 - 1701. British Museum.
    11. Table Clock. Made by Stephen Brenner 1526-1575. Verge and balance escapement replaced with pendulum. British Museum.
    12. Table Clock. Made by Lucas Weydmann 1648. Verge and balance escapement replaced with pendulum. British Museum.
    13. Longcase Clock. Made by Joseph Knibb about 1675. British Museum.
    14. Longcase Clock. Made by Edward East, late 1600s. British Museum.
    15. Shepherd Clock. From Horologica.
    16. Electrical motor clock. From Royal Museums Greenwich.
    17. Shepherd Clock. From Royal Observatory Greenwich.
    18. Riefler Clock. From NIST.
    19. Shortt Clock. From Wikipedia.
    20. Shortt Clock. From NIST.
    21. Shortt Clock. From Royal Museums Greenwich
  12. Balance Wheel Clocks
    1. Wooden Balance Wheel Clock. YouTube video.
    2. Balance Wheel and Spring Clock. YouTube video from Brian Law.
    3. Pierre II Huaud, Gold and Enamel Pendant Watch. Balance spring watch from 1685. YouTube video from The Frick Collection.
  13. Escapements
    1. Escapement Animations. Amazing set of escapement animations from Ken Kuo.
    2. Anchor Escapement. Anchor escapement with recoil. YouTube video from Ian Trowbridge.
    3. Recoil Anchor Escapements. Detailed YouTube video from National Watch and Clock Museum, NAWCC.
    4. Deadbeat Anchor Escapements. Detailed YouTube video from National Watch and Clock Museum, NAWCC.
  14. Navigation and Longitude
    1. Latitude and Longitude. From Smithsonian National Air and Space Museum.
    2. Latitude and Longitude. From timeanddate.com.
    3. Latitude and Longitude Map. From Maps of World.
    4. Portolan Chart by Pietro Vesconte. From the British Library.
    5. The Ages of Exploration. From the Mariners' Museum and Park.
    6. Looking for the Longitude. Hogarth Illustration.
    7. Brouwer's Indian Ocean Route. From Duyfken.
    8. Cook's Three Voyages of Exploration. From the Museum of Applied Arts and Sciences.
    9. Royal Museums Greenwich. From the Royal Museum of Greenwich.
    10. Celebration of the English Watch Part II. From Sothebys.
    11. Harrison's Longitude Clocks. From the Royal Museum of Greenwich.
    12. Harrison's H1 Clock. From the Royal Museum of Greenwich.
    13. Harrison's H2 Clock. From the Royal Museum of Greenwich.
    14. Harrison's H3 Clock. From the Royal Museum of Greenwich.
    15. Harrison's H4 Clock. From the Royal Museum of Greenwich.
    16. Earnshaw Chronometer Watch. From the British Museum.
    17. John Arnold Clocks and Watches. From the British Museum.
    18. Thomas Earnshaw Clocks and Watches. From the British Museum.
    19. Josiah Emery Clocks and Watches. From the British Museum.
    20. Thomas Mudge Clocks and Watches. From the British Museum.
    21. Cassini Map of France. From the Osher Map Library, University of Southern Maine.
    22. Cassini Maps. Biography of Cassini by Gabriella Bernardi.
    23. Descripcion de las Yndias Ocidentalis. Map of Spanish Hemisphere of Influence. From the Osher Map Library, University of Southern Maine.
  15. Standardization of Time
    1. Mail Coaches. From The Postal Museum, United Kingdom.
    2. Postal Route Maps. From The Postal Museum, United Kingdom.
    3. Mail Coach Guard Timepiece. From The Royal Mail, United Kingdom.
    4. The National Railway Museum. United Kingdom.
    5. Stephenson's Rocket. The National Railway Museum, United Kingdom.
    6. Drake's Map of the Grand Junction Railway. Bodleian Library, University of Oxford.
    7. Smith's Railway Map, 1836. Science Museum Group.
    8. The Corn Exchange Clock, Bristol. From Atlas Obscura.
    9. Riding the Rails. History of Rail in the US.
    10. Comparative Timetable. From the National Museum of American History.
    11. Synchronzing Time. From the National Museum of American History.
    12. The Day of Two Noons. Extensive documentation from the Library of Congress.
    13. Greenwich Time Ball. From the Royal Museum of Greenwich.
    14. Greenwich Time Ball Dropping. Youtube video.
    15. Time Ball, USNO. From APOD.
    16. Submarine Cable Map From TeleGeography.
  16. Watch and Clock Industry
    1. Revolution!. Clocks in 19th century America. From the National Museum of American History.
    2. Watches by Machine. From the National Museum of American History.
    3. Eli Terry Mass-Produced Box Clock. From the National Museum of American History.
    4. Jerome Brothers Ogee Clock. From the National Museum of American History.
    5. William Ellery Model Pocketwatch. Popular during the Civil War. From the National Museum of American History.
  17. Electronic Clocks
    1. How a Quartz Watch Works. YouTube video by Steve Mould.
    2. Quartz Versus Mechanical Watches. YouTube video by Teddy Baldessarre.
    3. Piezoelectricity. YouTube video by Steve Mould.
    4. How to Squeeze Electricity out of Crystals. YouTube video by TED-Ed.
    5. Resonance. Animation from PhET.
    6. Quartz Clocks and Watches. From ExplainThatStuff.
    7. Quartz Clocks Innards. From Marty Jopson.
    8. Greenwich Time Signal. From Wikipedia.
    9. Quartz Crystal Time Standard. From NIST.
    10. USNO Quartz Clock. From the Museum of American History.
    11. Quartz Watch History. From Engineering and Technology History Wiki (ETHW).
    12. Seiko Astron. From Seiko.
  18. Atomic Clocks
    1. Magnets and Electromagnetics. From PhET.
    2. Faraday's Law. From PhET.
    3. Charges and Fields. From PhET.
    4. Waves on a String. From PhET.
    5. The Electromagnetic Spectrum. From NASA.
    6. Rutherford Scattering. From PhET.
    7. Hydrogen Spectrum From McQuarrie and Simon.
    8. Emission Spectra From Southeastern Louisiana University.
    9. Models of the Hydrogen Atom. From PhET.
    10. Brief History of Atomic Clocks at NIST. From NIST.
    11. NIST F1 Atomic Clock. From NIST.
    12. NIST F2 Atomic Clock. From NIST.
    13. How an Atomic Clock Works. YouTube video from engineerguy.
    14. Cesium Clocks. YouTube video from CuriousMark.
    15. Louis Essen. From the National Physical Laboratory (UK).
    16. Applications for Atomic Clocks. From SPIE.
    17. AccuBeat. Commercial atomic clocks.
    18. Microsemi. Commercial chip-scale atomic clocks.
    19. Atomic Clock Markets. From Research and Markets.
    20. NASA Deep Space Atomic Clock. From NASA.
    21. Fountain Clock Keeps Good Time. From APS Physics.
    22. Hubble Space Telescope. From NASA.
    23. Event Horizon Telescope. From NASA.
    24. ESO Black Hole Page. From ESO.
    25. Radar and the Doppler Effect. From Robert Slade.
    26. How LORAN Works. From US Space Force.
    27. How GPS Works. From sciBRIGHT.
    28. How GPS Works. From Casual Navigation.
    29. How GPS Works. From US Space Force.