| dc.description |
The construction of the instrument described below was undertaken in the hope of providing a means for ascertaining at a glance the magnetic character of the day. The great accuracy attainable with modern magnetic instruments often renders the fickleness of the Earth's field a serious source of error. If it were possible to observe the “magnetic weather” conditions whenever desired, much time would be saved, and better results obtained in the comparison of instruments, determination of constants, etc. Moreover, it is of well recognized importance for certain investigations to make especially accurate records of the magnetic variations at times of disturbance; hence, an instrument giving some intimation of the presence of a magnetic storm would be valuable as a warning to make eye‐reading observations or to start the magnetograph at high speed. |
