1950 年 28 巻 11 号 p. 407-418
The aim of this paper is to investigate the mechanical properties of the astatic-magnet variometer, which is being used recently for the particular observation of minute variation of geomagnetic field. The characteristic feature of this apparatus is noted comparing with the single-magnet variometer. The sensitivity of the astatic-magnet variometer is defined both in the statical and dynamical cases, and the most convenient method for measuring sensitivity is discussed. Finally, the experimental results made at Kakioka Magnetic Observatory are shown in connection with the above discussion.