Accurate Clock Pendulums


Book Description

The Shortt clock, made in the 1920s, is the most famous accurate clock pendulum ever known, having an accuracy of one second per year when kept at nearly constant temperature. Almost all of a pendulum clock's accuracy resides in its pendulum. If the pendulum is accurate, the clock will be accurate. In this book, the author describes many scientific aspects of pendulum design and operation in simple terms with experimental data, and little mathematics. It has been written, looking at all the different parts and aspects of the pendulum in great detail, chapter by chapter, reflecting the degree of attention necessary for making a pendulum run accurately. The topics covered include the dimensional stability of different pendulum materials, good and poor suspension spring designs, the design of mechanical joints and clamps, effect of quartz on accuracy, temperature compensation, air drag of different bob shapes and making a sinusoidal electromagnetic drive. One whole chapter is devoted to simple ways of improving the accuracy of ordinary low-cost pendulum clocks, which have a different construction compared to the more expensive designs of substantially well-made ones. This book will prove invaluable to anyone who wants to know how to make a more accurate pendulum or pendulum clock.




NAWCC Bulletin


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Horological Journal


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NIST Technical Note


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Electronic Technology


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Ordnance Maintenance Wrist Watches, Pocket Watches, Stop Watches and Clocks


Book Description

This vintage book contains a handbook of watch repair and maintenance for ordnance maintenance personnel published by the American War Department in 1945. With useful diagrams and full instructions, this volume will be of considerable utility to those with an interest in vintage military watches. Contents include: "General", "Introduction", "Functional Description", "Inspection", "General Maintenance", "Cleaning and Lubricating", "Trouble Shooting, Adjusting, and Repair", "Pocket and Wrist Watches", "Characteristics of Pocket and Wrist Watches", "Hamilton Pocket Watch, 16 Size, 21-Jewel, Railroad Grade, Model 922B", et cetera. Many vintage books such as this are increasingly scarce and expensive. We are republishing this volume now in an affordable, modern edition complete with a specially commissioned new introduction. First published in 1945.




It's About Time (eBook)


Book Description

Help children measure and tell time by the sun, the clock and the calendar; and learn why there are 24 hours in a day, 7 days in a week and 365 days in a year. Here's a cross-curriculum approach to time with learning activities that bring together history, science, language arts and math. A comprehensive look at time from the ancient civilizations who first tried to understand, arrange and measure it - to modern society where we organize our lives around the clock!




Standardization in Measurement


Book Description

The application of standard measurement is a cornerstone of modern science. In this collection of essays, standardization of procedure, units of measurement and the epistemology of standardization are addressed by specialists from sociology, history and the philosophy of science.




The New Cosmos


Book Description

to the Second Edition The development of astronomy in the last ten years has been nothing short of explosive. This second edition of The New Cosmos, considerably revised and enlarged, tries to share this development with its readers. Let us mention a few key words: from mo on landings, planetary probes, aild continental drift through pulsars, X-ray and y-ray sources, interstellar molecules, quasars, and the structure and evolution of stars and stellar systems right up to cosmological models. As before, the most important task of this book is to give a not too difficult introduction to present-day astronomy and astrophysics, both to the student of astronomy and to the specialist from a neighboring discipline. We therefore draw to the attention of the reader, as an essential part of our description, the numerous illustrations-many of them new-and their detailed captions. As far as possible we link a description of important observations with basic features of the theory. On the other hand, when it comes to detail we often content ourselves with abrief description, leaving the detailed explanation to the specialist literature. The transition to the specialist literature should be eased by the Bibliography at the end of the book. Important new investigations are noted in the text by their year, not so much for historical reasons as to enable the original work to be found in the Astronomy and Astrophysics Abstracts (1969 on).