VERSUCHE ZUR AUSNUTZUNG VAGABUNDIERENDER STRÖME IN DER GEOPHYSIKALISCHEN PROSPEKTION.*

The experimental recording of the three components of the diurnal intensity of the stray currents in a mine shaft outside the region of mining activity of Freiberg has shown the uninterrupted presence of these currents with periods ranging from a few minutes to a few hours. It is demonstrated from theory and by model experiments that prospection by stray currents, utilizing telluric measuring methods, is feasible when the ratio between the distance to the sources of the stray currents and the size of the surveyed area exceeds a limiting value which depends on the accuracy of the measurements. To obtain an economic procedure it is necessary to replace the classical telluric technique by a vectorial recording method.

From a field example in the vein deposit of Freiberg it is shown that stray currents of arbitrary direction, and also telluric currents, are canalized by veins of anomalous conductivity. Other examples are given of underground measurements of stray currents, which were carried out for studying conductivity anomalies.