Description: The book is written in French in a very understandable way and describes what criteria are needed to buy a good watch from a reliable watchmaker. Watch distributors being not knowledgeable enough to sell good watches and also some sources for specific material used for watchmaking are mentioned. A whole section is dedicated to the explanation of the equation of time and why a watch or clock can not automatically show the ‘real’ solar time, unless it has the equation of time function (very much studied by Berthoud).
Provenance: Ex imperial library Vienna, Ex private collection Britanny
Additional Info:
At the end of the book one can find tables for the equation of time and four engravings to fold out, showing several mechanical drawings of watch -and clock movements and some of their parts.
This book, written by Ferdinand Berthoud, explaining how to regulate, adjust and keep running watches and clocks properly, shows the gilt coat of arms of the Empress Maria-Theresia of Austria (1717 – 1780), mother of Marie-Antoinette, on the front and back cover. It was part of the imperial library in Vienna until its transfer to a private collection in Britanny, France towards the middle of the 19th century, where it was kept by an aristrocratic family until it was passed on to a Swiss private collection.
Antiquarian Horology 
