A better course would be an inclination compass, even better would be a magnetometer. By the way, as is or will be shown somewhere, described measurement so for over 100 years ago, Mr. Pockels (1898,;-o), and knew very well that geomagnetic field variations at different locations are caused by the lightning discharge.
Kwa njia, kama ni au yanaweza Inavyoonekana mahali fulani, hivyo Ikielezewa kipimo kwa zaidi ya miaka 100 iliyopita, Mheshimiwa Pockels (1898,;-o), na vizuri sana Alijua Hiyo tofauti shamba Geomagnetic katika maeneo mbalimbali ni Husababishwa na kutokwa umeme.