in Metalliferous Veins. 13 



between the two points, or when the bad conductors breaking 

 the chain are of small extent, as, for example, merely a cross- 

 course, then, naturally, the heating of one of the discs has a 

 much more decided, or even a preponderating influence. 



As, now, the strongest currents were observed exactly where 

 the two points were separated by a non-metallic conductor, 

 there remains only the hydro -electric action of the metal- 

 lic components of the vein, to be assumed as theii' main cause. 

 Upon this hypothesis, the non-metalliferous rock represents 

 the moist conductor of the two connected masses of ore form- 

 ing the electrometer. Thus, when at the contact of the two 

 ore masses with the rock, exactly the same substances do not 

 occur, a current ensues, and this would almost ever be the 

 case. It is also possible, however, that the two ore masses 

 should have one, in every respect the same, metallic compo- 

 nent, e.g. consisting only oi galena, in which case, no current 

 could ensue. It is possible that the negative results of Strom- 

 beck and Fox originate in this. 



In order to prove the correctness of this hypothesis, we must 

 in every case know thoroughly the nature of the mass of ore, 

 and thence be able to predict the result. This is, however, 

 impossible. To contribute something to the subject, I ex- 

 amined, by means of the multiplicator, the series in which the 

 ores, that most generally present themselves in the mass, hei'e 

 follow one another, by dipping them in vei'y dilute sulphuric 

 acid, and found 



+ Zinc, 



Copper, 



Red silver-ore (not quite free from silver-glance), 



Galena^ 



Silver-glance (brittle and ductile mingled), 



Arsenical pyrites. 



Copper-pyrites, 

 — Iron-pyrites, 



results varying from those of Pfoff and Ritter. Red silver- 

 ore (Rothgiltigerz) is a very bad conductor. Blende so bad, 

 that no current was obtained from it, and thus its place could 

 not be determined. An application of this series can be made 



