This is a scholarly book on John Harrison, concentrating on and culminating in his Royal Astronomical Society (RAS) Regulator. Harrison began work on the Regulator in about 1750 and it remained unfinished when he died in 1776. He claimed that the Regulator would be capable of an accuracy of 1 second in 100 days. Such accuracy was not achieved until 1927 (Shortt Clock). The author is building the RAS Regulator according to Harrison's original intentions, to determine if such accuracy could have been achieved in the late 18th century.

The book includes the relevant scientific and aesthetic background of the period, and quotes from Harrison's own writings.  Excellent detailed drawings are provided of the regulator as the author believes Harrison intended it to be made; dimensions are taken predominantly from Rupert Gould's Notebook (1927), and photogrammetrically from the clock as it is today.  The most important mechanisms of the regulator are analysed geometrically and algebraically (A Level Maths).  This is not a beginners 'how to make a clock' book; its audience is experienced horologists, clock collectors, clock designers, horology students, and scientific historians.  

The book is beautifully written and clearly laid out.  It is well illustrated with photographs, together with period and modern drawings, sketches and diagrams.  This is without doubt the finest horological book I've had the pleasure to review since 'Woodward on Time'.

R.B.

ISBN 978-184426-773-6

Pub. Fionchra Press, Orford, Suffolk, UK.

£47.50 + P&P Available from www.shentonbooks.com