ill MelalliferoKd rdiis. 5 



times massive galena pi'esented itself at both points, three 

 times only at one, arsenical or iron pyrites or blende being at 

 the other. The pyrites and blende were, however, in unin- 

 terrupted connection with extensive deposits of galena. In 

 the experiments made at nearly the same level, the current 

 went /?^•e times from S. to N. in Frisch Gliick, and once from 

 N. to S. In Gottlob, E. and W. vein, from E. to W. In the 

 experiments, where one point lay above the other, the direc- 

 tion Avas Uvice downwards, and once upwards. These results 

 indicate that the direction of the current is quite independent 

 of its position, relatively to the axis of the eai'th, as well as of 

 the depth, but they are not sufficiently numerous for the com- 

 plete establishment of the fact. 



The deviation generally increased with the distance of the 

 two points, for in Gottlob, E. and W. vein, with the distance 

 10"', — a cross-vein causing a {hroiv intervening, — the devia- 

 tion was 23". In Frisch Gliick, with 14™, Avorked out space 

 and shafts intervening, 17°, at 50'" 54°, at G4"^ 63', at 68'" 51^ 

 at TC" 67=, at 88™ 71°, but at 126™ only 36' was obtained, 

 upon which latter we must remark, however, that blende was 

 the mineral at one point, and the small deviation may be at- 

 tributed to the bad conducting power of this substance. On 

 the other hand, it v/as under the same circumstances that, at 

 70" distance, the needle deviated 67°. 



Two galena points at 12™ distance, were connected by 

 means of a wire only 16™ long, and much thicker than the 

 fine one usually employed, upon which the deviation rose 

 from 17' to 25°, — a circumstance proving, that the resistance 

 to conduction encountered by the current in the muss of rock, 

 is not so gi-eat that the resistance in the 180™ long, .04"' 

 thick, wire, can be e*itirely neglected. 



In the two experiments between galena and blende, tlie 

 current was in the direction of the blende, and in those be- 

 tween the galena and {)yrites, always in the direction of the 

 galena. 



To meet tlic objection, that the cojtper diics might have 

 l)cen of different sorts, and that thus an action ensued, the 

 two discs were changed during an experiment, without obtain- 

 ing the least dilierence of result. K better prooi' that the 



