Horology

Abstract

IT is now about eight years since the previous edition of this book was sold out, and a measure of the esteem in which it was held by horologists is that second-hand copies were unobtainable. Its reappearance is therefore very welcome. The book commences with a clear exposition of the fundamentals of time and time measurement, which are treated at considerably greater length than is usual. The section on pendulums deals principally with those types used in precision clocks ; it is unfortunate that the question of temperature compensation and temperature errors is not treated quantitatively, as this does not require difficult mathematics, such as the author has evidently taken much trouble to avoid. Also there is no mention of the magnitudes of circular and barometric errors. A point of terminology which seems doubtfully correct is the use of the term a ‘free' pendulum, since all clocks described as having ‘free' pendulums have their pendulums, in fact, coupled to constant-force escapements of one kind or another. The term, however, has a wide usage among horologists, and it is perhaps as well to retain it.

Horology

The Science of Time Measurement and the Construction of Clocks, Watches and Chronometers. By J. Eric Haswell. With Supplement. Pp. xvi + 288 + 19 plates. (London : Chapman and Hall, Ltd., 1947.) 16s. net.