in Metalliferous Veins. 11 



on the gneiss opposite, which was as dry as can be the case in 

 mines where the air is always saturated with humidity. Tlie 

 needle deviated Qh°, and the current continued in the same 

 direction as before. Upon this, the same disc was applied 

 again to gneiss, but that at only 9 inches' distance from 

 the said galena, and the deviation was 18° Avith the current 

 still in the same direction. When the disc was connected by 

 means of a metallic chain with the galena, the deviation im- 

 mediately increased. From these experiments, it appears to 

 be a consequence, that, when the one disc is set on a non-me- 

 tallic point in the vicinity of ore, a current ensues, and this the 

 stronger the less removed the ore is. Now, as we found, on 

 the 6th drift, by connecting a galena point of Frisch Gllick 

 with non-metalliferous heavy-spar in Neu Hoffnung, a devia- 

 tion of 10^, the Bergmeister, Mr Fischer, ordered this point to 

 be worked out, and at 0.8"^ distance, dark and light red silver- 

 ores, and silver-glance, were found, which otherAvise should 

 never have been won. 



A result so favourable seemed naturally to demand a fur- 

 ther research into the matter ; still it cannot be denied ^hat 

 several other facts very much decreased the hope of the pro- 

 bability of an application of this means for detecting hid- 

 den ores. For example, on the 4th drift, a galena point in 

 Frisch Gliick was connected with non-metalliferous heavy-spar 

 in the sole of Neu Hoffnung, beneath which, at 8 metres' 

 distance, the existence of rich silver-ores was known of, with- 

 out any trace of an action being obtained, although in the 

 vicinity, upon iron-pyrites, in a cross vein of quartz, 20° devia- 

 tion was obtained. The distance of the ore must, then, be 

 very short, in order to have any indication of it by a current. 

 On the other hand, I obtained from gneiss, of the adjacent 

 country, in connection with galena, a deviation of G" ; in which 

 case, however, it must be mentioned, that the gneiss was wet, 

 and that at a distance of two metres, a vein containing pyrites 

 crossed. Further, upon heavy-spar, in the vicinity of a string 

 of pyrites, Avhich had caused deviations of 68° and 47°, there 

 was no action. 



There remain, consequently, for the solution of this ques- 

 tion, so important to the miner, further experiments to be 



