the Galvanic Current through Iron. 7 



sisting in the ratio of the intensities of the magnetizing and 

 the principal current, and to which I shall further on attach 

 my theoretic considerations. From these causes the numbers 

 of the following Tables show great diversity. 



Of the series of experiments with weak magnetizing cur- 

 rents, some are already serviceable before the improvement of 

 the magnetizing-apparatus. I denote by: — H the electromo- 

 tive force generating the principal current, M that producing 

 the magnetizing current; D the electromotive force of a Da- 

 niell, B that of a Bunsen element ; n the number of turns of 

 the magnetizing spiral ; I the approximate length, ol the thick- 

 ness, of the iron or steel wire ; w the resistance of the same, 

 measured in Siemens units, for M = 0, w the same for M>0 ; 

 w k the resistance of the copper conducting- wires to the resist- 



ance-box ; 8 the quotient ; t the time occupied by the 



experiment*. 



Passing over the time-details of the phenomena, I first give 

 only the numbers hereto belonging. 



1. H = M = 1 D ; n = 106 ; (annealed iron wire /i) 

 d = about 0*5 millini. 



w Q +w k iv + ic k w + iv k (w k = G'520Q) 



1-0300 1-0296 1-0304 8= -0-0012. 



2. H, M, n, as before. f v 

 w Q + w k w + w k w Q + w k (?^=0-5211) 

 1-0304 1-0294 1-0302 5= -0:0018- 



3. H, M, n as before. (Annealed iron wire f 2 ) d about 

 0*5 millim. 



w + w k io + iv k iv + w k (iv k = 0*5210) 



1-7478 1-7459 1-7476 S=-0'0015. 



4. H and M as before; n = 166. Wire/x. 

 w o + w k iv + iv k w o + w k (wj. = 0*5201) 

 1-0227 1-0216 1-0229 S=-0'0024. 

 Mean of 1-3, 8= -0-0015, while in 4 8= -0*0024. 



The magnetizing force is proportional to n : according to 

 the above, therefore, 8 is proportional to the magnetizing 

 force. According to its sign, 8 is negative. The length of 

 the wire (experiment 3) appears to be without influence. 



* Unfortunately, in most of the older experiments some of these data 

 are wanting-, it not haying- been anticipated that they would he required. 



