[15.]Increasing or Decreasing the Extremes of Temperature.
The extremes of 40° and 90° Fahr. have been used for the reason that they are best suited for general purposes. When it is known, however, that a watch is to be used in a warm climate the extremes may be raised five or ten degrees to advantage. If the watch is to be used in a cold climate, the extremes may be lowered this amount. The metals, however, can only stand the strain of expansion and contraction to a certain degree, and still maintain the positive qualities. Therefore it is quite important that the extremes be not raised or lowered very much beyond these figures.
CHAPTER IV
SOME PRACTICAL METHODS OF CORRECTION
[16.]Example of Maintaining a Pleasing Appearance of the Balance.
In altering the location of screws during the temperature adjustment it is often possible to either mar or improve the appearance of the balance. As a demonstration of this point the correction made in regard to Fig. 3 is analyzed. The balance had twelve screw holes in each rim, with the space between the first and second holes from the arms equal to double the space between any other two holes. There were seven screws in each rim, equally divided as per cut Fig. 5, which indicates screws in the first, second, fourth, sixth, eighth, tenth and twelfth holes.
Fig. 5