ELECTRICAL ACTIVITY OF ORE BODIES. 



345 



case coincides with Point VIII. and is in porons limestone. The great 

 ore bodies have been lettered as in Fig. 27. Ore is also found at G, above 

 and below the GOO-foot level, and at n above it. U V xa a line of contact 

 between the shale of the west country and limestone. Table XIII. exhibits 

 more exactly the disposition, etc., of the points. It will be intelligible with- 

 out further explanation. (Cf Table IX., page 338.) 



Table XIII. 



The results of the measurements of electromotive forces between VIII. 

 (P. C.) and the T. C's are contained in Table XIV. The nomenclature being 

 the same as that used above, the meaning of the data will be at once appar- 

 ent. As before, four terminal bags. A, B, C, and D, were used. Intensi- 

 ties are given in electronic gnetic units (C. G. 8.), electromotive forces in 

 volts; -and are arbitrarily considered positive when the ]->otential of T. C. is 

 o-reater than that of P. C. (Point VIII.); or when the current travels 



J. C >{ ^i >P. C. The experiments were made in continuous 



( tvire ) 



series, starting with Point I. in the extreme west, in shale, and ending with 

 XXL, near the shaft, in limestone. Water, which had previously been 

 kept in contact with zinc, was used as an outer liquid. 



