PURPOSE: To measure frequency of the earth vibration encircling the sun by measuring the cycle of a pendulum (weight) in which an angle of oscillation varies by the Foucault's theory.

CONSTITUTION: This measuring apparatus comprises a mounting section (ceiling) 1, a cord 2, a weight 3, a reference line 4 and a graduation plate 5. The graduation plate 5 serves as yardstick when a pendulum is oscillated and an angle of oscillation thereof varies by the Foucault's theory. Therefore, it is very important to keep a ball from turning when the pendulum is oscillated. If the ball should spin, the pendulum is kept oscillating for a while and it returns to the normal condition. A line put on an steel ball turns to the right or to the left and when the motion becomes stable in cycle, frequency can be learned by counting a time length of the cycle or rotation of the cycle for a certain fixed time.