in Magnetism and Electricity. 



89 



identical in every respect with those observed when the electrodes 

 were only a few feet apart. Thus a series of thirty-three Daniell's 

 cells indicated 10° of current on the galvanometer at N, whether 

 the distance between the ring-electrodes was 3 feet or 300 feet ; 

 while with the quantity- and intensity-currents from the 5- and 

 10-inch electromagnetic machines the opposite effects of resist- 

 ance, as manifested by the non-heating of thin wire at N, were 

 obtained, whether the ring-electrodes were at the greater or at 

 the less distance (113). 



123. Again, when the conductors were uncoiled and extended 

 in the canal 300 feet from each other, the currents from the 5- 

 and 10-inch intensity-armatures melted and made red-hot the 

 same lengths and thicknesses of wires at N as when the conduc- 

 tors were extended in the canal 9 feet apart ; while, on the other 

 band, the currents from the 5- and 10-inch quantity-armatures 

 encountered the same resistance, as manifested by the non-heating 

 of the wires at N, at the greater as at the less distance (115). 



124. The following Table contains the results of a carefully 

 made series of experiments with different numbers of similar 

 Daniell's cells, when the ring-electrodes were immersed in the 

 canal at distances of 3 and 300 feet from each other. 



Table V. 





"Deviation of gal- 



Deviation of gal- 



Deviation of galva- 



No. of Daniell's 



vanometer with 



vanometer when 



nometer when dis- 



cells in series. 



battery in short 



distance between 



tance between elec- 





circuit. 



electrodes = 3 feet. 



trode = 300 feet. 



1 



95 



375 



375 



2 



100 



575 



575 



5 



100 



7-50 



7-50 



11 



100 



875 



875 



22 



100 



975 



975 



33 



100 



10-0 



100 



125. The results contained in columns 3 and 4 of the above 

 Table prove conclusively that no change whatever occurs in the 

 electric condition of the earth in consequence of a mere change 

 in the distance of the electrodes from each other. It will also 

 be evident that variations in the intensity of the battery-current 

 are sufficient to produce corresponding changes in the resistance 

 of the earth similar to those produced by the quantity- and in- 

 tensity-currents from the electromagnetic machines when the 

 conductors were extended in the canal (114, 115). 



126. Returning to a consideration of the effects produced by 

 the alternating current from the 5-inch intensity-armature when 

 the ring-electrodes were connected with the aerial conductors of 



