Pages 65-72
In this paper, the authors report the result of calibration of a torsiograph which is generally regarded as good in accuracy. For a considerable period of time, we have had a few doubtful records among many cases, which might be due to the effect of measuring equipment and method. Therefore, we made the calibration and obtained the test result as follows. 1) Geiger's torsiograph had a good accuracy when there are no effect of vibration of the. belt and foundation. 2) The resonance at the natural frequency of torsiograph was not observed. 3) The effect of vibration of the driving belt to the recorded amplitude was very severe. 4) The effect of vibration of the foundation in the vertical and belt direction below 30 cps is scarecely observed.