THE 



EDINBURGH NEW 

 PHILOSOPHICAL JOURNAL. 



Besearches on the Electrical Currents in Metalliferous Ferns, 

 made in the Mine " Himmelfahrt," near Freyberg. By Pro- 

 fessor F. Reich of Freyberg. Communicated by the Author. 



Since Fox first discovered the fact* in copper-veins in Corn- 

 wall, it has been known that an electrical current is indicated 

 by Schweigger's Multiplicator, when two points, where ore 

 presents itself, are connected by metallic wire, whether these 

 be in the same or in different veins. Fox repeated the expe- 

 rimentsf in lead-veins in other parts of England with similar 

 success. On the other hand, Von Strombeck+ could find no 

 trace of such electrical currents in lead and copper veins on 

 the right bank of the Rhine. Again, Kenwood repeated the 

 experiments in Cornwalk§ and confirmed former results. 



I have made similar experiments in the mine " Himmel- 

 fahrt" in this district, leading to very decisive positive results. 



The method of experiment was in the main that of Fox. 

 When the tv/o points to be connected were determined, a fresh 

 surface was first worked on each, and on this a six inches long, 

 three inches wide, disc of copper, was kept firmly pressed by 

 a woodeh strut. An uncovered end of a copper-wire, spun 

 over with silk, was kept pressed to the copper-plate by means 

 of a clamp. The one wu-e A\as always short ; the other, about 

 180 metres long, was rolled on a pirn. This latter was re- 

 tained in all the experiments, the current having thus the same 

 length of wire to pass, so that its influence on the amount of 

 deviation from the needle was constant. The long wire was 



* Phil. Trans. 1830, ii. p. 399. 



t Transactions Roy. Gcol. Soc. of Cornwall, vol. iv. p. 29. 

 i Kaihtcn's Arcliiv iiir lit if^biiu, &c., vol. vi. p. 431. 

 S Milling llcvicw. No. x. p. 214, 1837. 

 VOI-. XXVIII. NO. LV. JANTAUY 1840, A 



