swans on tea

Just another SFN Blogs site
  • Home
  • A very little about me
  • Sample Page

"Classic" Timekeeping, Part I: Introduction

Published by swansont on May 28, 2008 03:56 pm under History, Physics, Tech, Time

Following the suggestion and subsequent reminder (nothing like a deadline to get the creative juices flowing) from gg at Skulls in the Stars, I’ve got two “old” papers that I’m going to summarize.

I recommend choosing something pre- World War II, as that was the era of hand-crafted, “in your basement”-style science. There’s a lot to learn not only about the ingenuity of researchers in an era when materials were not readily available, but also about the problems and concerns of scientists of that era, often things we take for granted now!

These are from 1931, fulfilling the pre-WWII criterion, when you still had individuals engaging in research that were self-financed or supported by a patron and much of the equipment was self-manufactured. The science in this case was largely self-funded, and as for the “basement,” well, it’s a pretty fancy basement as you’ll see, as one might suspect of someone who can fund his own science. But classic nonetheless. There’s a bit to do, and I’m going to break it up into more manageable chunks.

The papers in question are from the Monthly Notices of the Royal Astronomical Society, Vol. 91, published in 1931, and are “The Precise Measurement of Time” by Alfred L. Loomis (p. 569-575) and “Time, Analysis of records made on the Loomis chronograph by three Shortt clocks and a crystal oscillator” by Brown, E. W. & Brouwer, D. (p.575-591). (I, know, I know. They sound like tabloid headlines, don’t they?) The first paper describes various apparati used, and the second describes a particular measurement that was of interest to me.


The measurement of interest came about from a question on pendulum clocks. Anyone who has taken introductory physics has seen that the frequency of oscillation depends on gravitational acceleration, and might have done a problem calculating the change in frequency or period for an elevation change. But what of another change in gravitational acceleration — what effect does the varying location and thus pull of the moon have on a pendulum clock? And has it been measured? In order to do that measurement, one has to compare a pendulum clock with another that does not depend on the local value of g. The period around 1930 saw a transition from pendulum clocks to quartz oscillators, and that fits the bill, since the quartz crystal, though sensitive to large accelerations, will not have nearly the sensitivity to this kind of change in g. These papers describe the equipment, measurement and the results.

The author of the first paper is Alfred Lee Loomis, a name with which I was not familiar prior to reading these papers, and I’m not sure how that happened. Loomis was a scientist and inventor, and could afford to do these as a hobby, because he was quite rich — he made his fortune in finance in the 1920’s and pretty much exited the stock market before the crash of 1929, so his fortune remained intact and allowed him to buy back on the cheap. He set up a laboratory at his mansion in Tuxedo Park, NY and performed experiments in various fields, including precise time, but also microwave radar. He helped develop that before the defense department was fully behind it, and was appointed to be in charge of the project. The development of radar technology was, of course, a significant factor in winning the war. You can read some more about him here and here.

The devices to be described are the two types of clocks that were used, the crystal oscillator and the Shortt pendulum clocks, and the device used to compare and record timing differences between them, the Loomis Chronograph. I’ll get into the technical aspects next.

Part II

No Comment

Comments are closed.

Posting your comment.

  • Recent Posts

    • When Does the Decade End?
    • This is the Hardest Job a Manager Has …
    • 5 Things You Should Know About Light
    • See Spot "Run"
    • The System Works
  • Recent Comments

    • Joey Cook on One Ringy-Dingy, Two Ringy-Dingy
    • Science Fanatic on Talk Like a Physicist Day
    • Chris Gould on Brian Cox is Full of **it
    • LaurieAG on Inmates Running the Asylum
    • Uncle Al on Curious About Curies
  • Archives

    • December 2019
    • February 2015
    • January 2015
    • December 2014
    • November 2014
    • October 2014
    • September 2014
    • August 2014
    • July 2014
    • June 2014
    • May 2014
    • April 2014
    • March 2014
    • February 2014
    • January 2014
    • December 2013
    • November 2013
    • October 2013
    • September 2013
    • August 2013
    • July 2013
    • June 2013
    • May 2013
    • April 2013
    • March 2013
    • February 2013
    • January 2013
    • December 2012
    • November 2012
    • October 2012
    • September 2012
    • August 2012
    • July 2012
    • June 2012
    • May 2012
    • April 2012
    • March 2012
    • February 2012
    • January 2012
    • December 2011
    • November 2011
    • October 2011
    • September 2011
    • August 2011
    • July 2011
    • June 2011
    • May 2011
    • April 2011
    • March 2011
    • February 2011
    • January 2011
    • December 2010
    • November 2010
    • October 2010
    • September 2010
    • August 2010
    • July 2010
    • June 2010
    • May 2010
    • April 2010
    • March 2010
    • February 2010
    • January 2010
    • December 2009
    • November 2009
    • October 2009
    • September 2009
    • August 2009
    • July 2009
    • June 2009
    • May 2009
    • April 2009
    • March 2009
    • February 2009
    • January 2009
    • December 2008
    • November 2008
    • October 2008
    • September 2008
    • August 2008
    • July 2008
    • June 2008
    • May 2008
    • April 2008
    • March 2008
    • February 2008
    • January 2008
  • Categories

    • admin
    • Antiscience
    • Art
    • Blog Compendia
    • Blogging
    • Body
    • Books
    • Bureaucracy
    • Business
    • Cartoon
    • Conference stories
    • Cool stuff
    • DIY science
    • Education
    • Environment
    • Experiments
    • Food
    • Game
    • Geocaching
    • History
    • Humor
    • Illusions
    • Journalism
    • Lab Stories
    • Language
    • Links
    • Math
    • Metaphysics
    • Misc
    • Movies
    • Music
    • Navy
    • Not Really Science at All
    • Other science
    • peeve
    • photography
    • Photos
    • Physics
    • Politics
    • Quotes
    • Rants
    • Religion
    • Satire
    • Sci-Fi
    • Science-general
    • science-y observation
    • Security
    • Shameless self promotion
    • Sick sick sick
    • Silly
    • Sports
    • Tech
    • The Lab
    • Thermal IR
    • Time
    • TMI
    • Toys
    • trivia
    • TV
    • TYAGFITI
    • Typography
    • Uncategorized
    • Video
    • Weird
    • World Events
    • Writing
  • Meta

    • Log in
    • Entries feed
    • Comments feed
    • WordPress.org

Copyright © 2023 swans on tea
WordPress Theme based on Light Theme