This volume chronicles the horological work carried out in France, Germany, and North America and completes the fascinating history of precision timekeeping in recent time. Over 500 beautiful color and black-and-white photographs illustrate the historical contributions of renowned clockmakers from France and Germany. America's contribution to precision timekeeping is chronicled along with recent advancements in precision pendulum timekeeping.

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.

Harrison Decoded: Towards a Perfect Pendulum Clock brings together the output of a forty-year collaborative research project that unpicked and put into practice the fine details of John Harrison's extraordinary pendulum clock system. Harrison predicted that his unique method of making pendulum clocks could provide as much as one-hundred-times the stability of those made by his contemporaries. However, his final publication, which promised to describe the system, was a chaotic jumble of information, much of which had nothing to do with clockwork. One contemporary reviewer of Harrison's book could only suggest that the end result was a product of Harrison's 'superannuated dotage.' The focus of this book centres on the making, adjusting, and testing of Clock B which was the subject of various trials at the Royal Observatory, Greenwich. The modern history of Clock B is accompanied by scientific analysis of the clock system, Clock B's performance, the methods of data-gathering alongside historical perspectives on Harrison's clockmaking, that of his contemporaries, and some evaluation of the possible influence of early 18th century scientific thought.

The pendulum is a constant source of interest to scientists. Great and well-known inventors such as Galileo, Huygens, and Kelvin all devised mechanisms to maintain its even oscillations. Others such as John Harrison, Lord Grimthorpe, and William Shortt are known only in horological circles but contributed as much or more over three centuries. By writing a personal account of his own inventions and achievements in horology the author involves the reader in the history of precision time-keeping before the advent of atomic clocks and the quartz chip. Escapements, the mechanisms that drive pendulums, are a delight to the geometrical mind as well as a delicate and subtle challenge to the mechanical engineer. In their most refined form pendulum clocks not only keep astonishingly accurate time they are also sensitive enough to detect the ebb and flow of tides and even the ceaseless quivering of the Earth itself. Philip Woodward's deep knowledge of and passion for time-keeping mechanisms is evident throughout this highly readable and fascinating account of precision horology.

This beautiful book relates the incredible story of how leading clockmakers, primarily of England, struggled to control accurate timekeeping for over 300 years. A remarkably thorough yet concise text, by several of todays leading horologists, is accompanied by nearly 1,000 photographs of clocks, which demonstrate each fascinating development. From museums of international significance, as well as private collections worldwide, the best examples of each new invention to establish accurate time-keepers is illustrated and recorded here. Chapters are devoted to the Royal Observatory at Greenwich and many of the brilliant men of science who made instruments and provided timekeepers. Georgian, Regency, and Victorian advances are shown to have contributed to the eventual success of accurately measuring time, that is so crucial to the success of todays highly integrated society.

If you want to know where you are, you need a good clock. The surprising connection between time and placeais explored inaTime and Navigation- The Untold Story of Getting from Here to There, the companion book to the National Air and Space Museum exhibition of the same name. Today we use smartphones and GPS, but navigating has not always been so easy. The oldest "clock" is Earth itself, and the oldest means of keeping time came from observing changes in the sky. Early mariners like the Vikings accomplished amazing feats of navigation without using clocks at all. Pioneering seafarers in the Age of Exploration used dead reckoning and celestial navigation; later innovations such as sextants and marine chronometers honed these techniques by measuring latitude and longitude. When explorers turned their sights to the skies, they built on what had been learned at sea. For example, Charles Lindbergh used a bubble sextant on his record-breaking flights. World War II led to the development of new flight technologies, notably radio navigation, since celestial navigation was not suited for all-weather military operations. These forms of navigation were extended and enhanced when explorers began guiding spacecraft into space and across the solar system. Astronauts combined celestial navigation technology with radio transmissions. The development of the atomic clock revolutionized space flight because it could measure billionths of a second, thereby allowing mission teams to navigate more accurately. Scientists and engineers applied these technologies to navigation on earth to develop space-based time and navigation services such as GPS that is used every day by people from all walks of life. While the history of navigation is one of constant change and innovation, it is also one of remarkable continuity. Time and Navigation tells the story of navigation to help us understand where we have been and how we got there so that we can understand where we are going.

This accessible reference presents the evolution of concepts of time and methods of time keeping, for historians, scientists, engineers, and educators. The second edition has been updated throughout to describe twentieth- and twenty-first-century advances, progress in devices, time and cosmology, the redefinition of SI units, and the future of UTC.