Page:Life in Motion.djvu/78

marker, c, fixed to the end of a steel spring, and armed with a mass of steel, somewhat wedge-shaped, which fits in between two small keepers. Fig. 27.—Electric chronograph. For description see text. b b, of the electro-magnets, a a. The tuning-fork interrupts the current from the battery. Fig. 28.—Interrupting or chronographic tuning-fork. This it does automatically. When the iron of the electro-magnet between the limbs of the tuning-fork becomes magnetic, the limbs are