38 Royal Society : — 



the third at the remote end near the communication with the earth. 

 When the connexion of the battery with the wire was completed, 

 the galvanometers were successively acted upon in the order of their 

 distances from the battery, as in the experiments recorded by Dr. 

 Faraday. When the earth connexion at the remote extremity of the 

 wire, on the contrary, was completed, the disturbance of equilibrium 

 commenced at this end, and the galvanometers successively acted in 

 the reverse order, i. c. the galvanometer which was the most distant 

 from the battery was the first impelled into motion. In the latter 

 case, before the completion of the circuit the needles of the galvano- 

 meters had assumed constant deflections to a limited extent, owing 

 to a feeble current arising from the uniform dispersion of the static 

 electricity along the M'ire. 



Exp. 5. The two extremities of the G60 miles of wire were brought 

 into connexion with the opposite poles of the battery. When one 

 of the ends previously disconnected from the battery was united 

 therewith, the galvanometers at the extremities of the wire, and con- 

 sequently which were at equal distances from the poles of the bat- 

 tery, were immediately and simultaneously acted upon, while that 

 which was in the middle of the wire was subsequently caused to 

 move. When the wire disconnected in the middle instead of near 

 one of the poles of the battery was again united, the middle galvano- 

 meter, which was the most remote from the battery, was the first 

 acted upon, and those near the poles subsequently. 



The comparison of the two above-mentioned experiments show 

 that the earth must not be regarded simply as a conductor, which 

 many suppose to be the case. Since in the first experiment there were 

 not many yards' distance between the two earth terminations, did 

 the extent of ground between them act only as a conductor, the two 

 galvanometers at the extremities of the wire should have acted simul- 

 taneously, as in the second experiment, and as would have been the 

 case had a short wire united the two extremities which proceeded 

 to the earth. 



Third Series. 



Exp. 6. One pole of the battery was connected with the earth, and 

 the opposite jiole with one extremity of the 660 miles of wire, the 

 other end remaining insulated ; a delicate galvanometer was interposed 

 near the battery. Notwithstanding there was no circuit formed, the 

 needle showed a constant deflection of 33|° ; the feeble current 

 thus rendered evident is not so much to be attributed to imperfect 

 insulation, as to the uniform and continual dispersion of the static 

 electricity with which the wire is charged throughout its entire 

 length, in the same manner as would take place in any other 

 charged body placed in an insulating medium. The strength of 

 the current thus occasioned appears to be nearly, if not exactly, 

 proportional to the length of the wire added, as the following table 

 will show : the first column indicates the number of miles of wire 

 subjoined beyond the galvanometer, and the second the correspond- 

 ing deflections of the needle : — <y 



