The Influence of Observatory Trials on the Progress of Chronometry

From Horology magazine, July 1938

The Influence of Observatory Trials on the Progress of Chronometry

The Journal Suisse d'Horolgerie has recently concluded an interesting series of articles on this subject. Opening the discussion the author traces the history of chronometric trials in the leading European observatories. He points out that the first tests for ordinary watches were given at the Geneva observatory in 1790 by the Societe des Arts. A total of 19 pieces were submitted.

Until 1847 manufacturers were allowed to select the tests to which their watches were submitted. This freedom of choice, however, did not provide any basis of comparison of competitive makes and in that year a series of uniform tests was adopted. They included trials in 6 positions and 3 temperatures.

While the observatory at Geneva was in existence prior to the institution of chronometric trials, the observatory at Neuchatel was created specifically for this purpose upon the demands of watch manufacturers in the vicinity. The first trials, started in 1860, required watches to be tested in only 2 positions. This was soon found inadequate and in 1873 the 5 position tests were adopted. In 1876 an annual prize award was created, which was given to the manufacturer submitting not less than 12 pieces and obtaining the best results. This was intended as a safeguard against awarding the prize for an isolated .piece. Later the requirements were changed from 12 to 6 pieces as the minimum. In 1873 the tests were extended to cover 5 positions and a few years later a third temperature test was added.

In France, the observatory at Besancon first inaugurated chronometric tests in 1885. These were based on the Geneva trials. Kew observatory, in England, likewise followed the Geneva trials when its own tests were started in 1884.

Coming to the technical portion of his subject, the author, E. Guyot, cites the results obtained at the N euchatel observatory with the various forms of escapements during the period 1862-1900. He follows with a comparison of the results obtained with various forms of hairsprings and balances. One fact stands out most clearly as a result of the figures quoted and it is that since the introduction of the Guillaume balance in 1899 the temperature variations have been greatly lessened and the secondary error reduced. Of the watches submitted to the observatory since that time, the number of brass and steel bimetallic balances dropped uptil in 1910 there were only 5 out of 181 watches which had them. The last portion of the article deals with the apparent improvement in the rate of a timepiece with an increase in its diameter.

The conclusions derived are summarized by the author in four statements:

1. They serve to stimulate the watch manufacturers by inducing them to make better products.

2. They play an important role in watch factory advertising. By improving business they are enabled to devote more money to chronometric research.

3. They supply important information about the various systems used: escapement, balance, hairspring, etc. and permit the elimination of unsatisfactory systems.

4. They contribute to the maintenance of a high standard of horological workmanship.