CHAPTER X. 

 ON THE ELECTRICAL ACTIVITY OF ORE BODIES. 



BY CARL BARUS. 



GENERAL STATEMENT. 



In 1830 R. W. Fox commuuicated to the Royal Society a paper which 

 contained the results of a careful experimental study of the possible electric 

 activity of ore bodies. From this time until 1 844 the matter was discussed 

 with some enthusiasm by Fox and Hen wood, in England, and by von Strom- 

 beck and Reich, in Germany. After the publication of Reich's second paper 

 (1844), however, further research seems to have been altogether abandoned; 

 at least I have not, with some pains, been able to find anything that has a 

 bearing on the subject.' This is all the more remarkable, as the general 

 line of investigation had already taken a promising direction. It would 

 also have been supposed that Thalen's^ work would have given the matter a 

 fresh impetus. 



With the present investigation (undertaken at the suggestion of Mr. 

 Becker^) the question of a relation between local currents and ore bodies 

 is, as it were, resuscitated, so that a general review of the development which 

 it had attained previous to its abandonment seems pertinent. 



' See, also, "Revue des Progres r^centes de I'Exploitation des Mines, etc., par M. Haton de la Goa- 

 pillifere, lugen. en chef des Mines, Professeur, etc.," in the Auualcs des Mines, T. XVI., p. 6, 1879. 



'R. Thalen; v. dela Goupillifere, /. c. : "On trace des lignes d'^gale iuteusitd, qui daus le voisi- 

 nage d'uu glte prennent une forme caract^ristique consistant en deux syst6mes de courbes fermees, con- 

 centriqiies, autour de deux foyers assez nettement indiqii€s." 



^Cf. : First Annual Report of the U. S. Geolog. Survey, p. 46, 1880. 



(309; 



