Page:Life in Motion.djvu/78

58 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.

b b, of the electro-magnets, a a. The tuning-fork interrupts the current from the battery.

This it does automatically. When the iron of the electro-magnet between the limbs of the tuning-fork becomes magnetic, the limbs are