in Magrtetism and Electricity. 87 



produced in the iron wires, the passage of a current through the 

 conductors into the earth. 



111. The current from the battery of thirty- three DanielFs cells 

 in series was first transmitted through the tangent galvanometer 

 in short circuit, when the needle stood permanently at 10°. 



112. When the same battery-current was transmitted into the 

 canal, through the conductors and electrodes arranged as in 

 tig. 12, the galvanometer introduced at N still indicated 10° of 

 current, thereby showing a null resistance on the part of the 

 water in the canal to the passage of the whole amount of current 

 which the battery was capable of producing. 



113. But on attempting to transmit the powerful alternating 

 currents from either the quantity- or the intensity-armatures of 

 the 5- and 10-inch machines into the canal through the same 

 arrangement of conductors and electrodes as in the preceding 

 experiment, the amount of current actually transmitted was not 

 sufficient to make three inches of the thin iron wire (107) intro- 

 duced at N sensibly warm to the fingers, the result now indica- 

 ting an almost total resistance to the passage of the current which 

 the electromagnetic machines were capable of producing. 



114. On uncoiling the two rings of copper rope and extending 

 them in straight lines, about twenty feet apart, along the bottom 

 of the canal towards the points 0, P, with the distant ends C, D 

 of the conductors entirely disconuected, the current from the 

 5-inch intensity-armature made two feet of iron wire *035 of an 

 inch in diameter bright red-hot at N, and the current from the 

 10-inch intensity- armature melted four feet of wire '050 of an 

 inch in diameter, the result now indicating a great diminution 

 of the apparent resistance of the earth to the passage of a pow- 

 erful electric current. 



115. But on attempting to transmit the current from the 5- 

 and 10-inch quantity-armatures through the conductors extended 

 in the canal, the amount of current now transmitted was only 

 sufficient to make fifteen inches of the thinner wire used in the 

 preceding experiment (114) sensibly warm to the fingers, the 

 result again exhibiting an increase of the earth's resistance 

 similar to that observed when the conductors were coiled up into 

 rings. 



116. Similar effects of resistance to the passage of the current 

 into the earth, as indicated by the non-heating of the thin wire 

 at N, were also obtained when the 2^-inch machine, or the single 

 Grove's cell, was connected with the submerged conductors in 

 their extended form. 



117. That this resistance to the passage of the current from 

 the 5- and 10-inch quantity-armatures and that from the single 

 Grove's cell was not due to the resistance of the copper conduc- 



