Answer:
The mass and pen
Explanation:
Seismograph is the device used for measuring the movement of earth such as earthquake, volcanic eruptions or other movements. A seismograph can record the motion as small a 1/10,000,000 cm. Seismograph consist a recording device. Now we have electronic seismograph but earlier we had pen and drum seismograph in which pen and mass remains stable and does not shake during movement.
