The general results obtained, and repeatedly verified, may be 

 briefly stated as follows : From the 110 yards to the greatest length 

 of 1 6 miles, it took from half to one and one quarter of a second for 

 the cable to receive as much of the charge of the whole battery as 

 could pass through the vacuum-tubes 219, the time being denoted 

 by the appearance of the luminosity in the negative ball (see fig. 3 A). 



With 110 yards the discharge of a charge previously given to the 

 cable was instantaneous ; it appeared to be nearly momentary with 

 one mile, and the time then progressively increased according to the 

 length of the cable previously charged, until with the 16 miles it 

 took one and a quarter to one and a half seconds before the luminous 

 glow on the ball in the vacuum-tube disappeared. 



It was beautiful to see the regularity with which the glow appeared 

 and disappeared in these experiments, first at one terminal and then 

 at the other, according as the cable was charged or discharged. 



After the cable had received the discharge to the greatest intensity 

 that could be obtained through the tube 219, the full charge of the 

 battery was then completed by cutting off the tube from the circuit 

 by means of a wire. On removing the wire, and substituting the 

 earth for the battery, a discharge took place ; but a residuary charge 

 was always found, which could not pass through the vacuum. If 

 this residuary was allowed to remain in the cable, and the battery 

 again substituted for the earth, no additional charge could be made 

 to pass from the battery through the vacuum-tube ; but so soon as 

 this residuary was discharged, the cable again became charged 

 through the tube as before*. 



We were particularly fortunate with these experiments ; for on 

 Mr. Wheatstone testing the capability or power of the battery, he as- 

 certained that on taking from it only 32 cells, thus reducing the num- 

 ber to 480, the discharge could not pass through the vacuum-tube. 



* If one of the wires of the vacuum-tube No. 219 is connected with the inner 

 coating of a Leyden jar, and the other with the prime conductor of an electrical 

 machine, when the machine is excited a luminous glow will be observed round 

 one of the balls, similar to that obtained during the charging of the cable by the 

 voltaic battery, and the jar will become gradually charged. On the excitation of 

 the electrical machine being stopped, if a pointed wire is presented to the prime 

 conductor, the jar will be gradually discharged, and the luminous glow appears 

 on the other ball of the vacuum-tube ; if several similar tubes are arranged in 

 series, and the jar is discharged through longer carbonic-acid vacua, the striae 

 can be obtained in the latter. 



