Читать книгу Rules and Practice for Adjusting Watches - Walter J. Kleinlein - Страница 22

In the foreign observatories where watches are generally tested for competition prize, or certificate purposes, they are subjected to either three or five day tests in each temperature, preceded by one intermediate day at normal temperature which is not considered in making the deductions. The purpose of this is to allow the metals to assume the natural condition before being placed in, or changed from, one degree of temperature to another. After the three or five day test, according to the grade of the watch, the average of the daily rates in each temperature is considered in making the comparison and arriving at the total variation. The total error is then considered in the summary, as a fraction of a second variation per each degree of temperature. As an example we will consider that the total error between the two averages is five seconds and that the difference in the two extremes of temperature was fifty degrees F. The variation would be given as one-tenth of a second per each degree of temperature.