184 Dr. Andrews on the Conducting Power, S^-c. 



which was filled with common alcohol, and another similar 

 wire was inserted into its open extremity. The positive end 

 of the pile being connected with the first wire, the second wire 

 became the positive pole, so that the column of alcohol formed 

 part of the circuit. When the positive pole was placed in the 

 flame of a spirit-lamp, and the flame touched by a wire in con- 

 nexion with the ground, the deviation of the leaf of the elec- 

 troscope attached to that pole ceased, while that of the elec- 

 troscope connected with the negative pole increased. This 

 showed that the positive electricity was freely transmitted 

 through both the flame and the cohmm of alcohol. When 

 both poles were inserted into the flame, their tensions, as in- 

 dicated by the electroscopes, did not sensibly diminish ; but 

 when the flame was touched by a wire connected with the 

 ground, the deviation of the leaf of the electroscope on the 

 negative side diminished, while that of the electroscope on the 

 positive side increased. The tendency appeared now no longer 

 in favour of the positive but of the negative electricity, which 

 proves that the flame always allowed a small quantity of the 

 latter kind of electricity to pass, and did not perfectly insulate 

 the poles of the voltaic pile. 



Although not connected with the subject of this paper, I 

 take the opportunity of observing that by employing a similar 

 contrivance on the negative side the tendency of alkaline soap 

 to conduct negative electricity may be apparently reversed ; 

 but for this purpose a column of alcohol ^yth of an inch in 

 diameter and jth of an inch long is sufficient, while in the case 

 of the flame of alcohol a similar column two or three inches 

 long is required. 



From the experiments which I have detailed, it is evident 

 that the conducting power of flames for electricity cannot be 

 explained by the diminished elasticity of the gaseous matter 

 which they contain ; nor does the conduction of a feeble cur- 

 rent of electricity by the flame of alcohol appear to be a par- 

 ticular case of the discharge of a powerful battery between 

 charcoal poles when separated after contact. The flame of 

 alcohol conducts the electricity of a single pair of plates even 

 when the poles are separated by a considerable distance, while 

 with a battery of far greater power no sensible separation of 

 the poles in air can be obtained without altogether interrupt- 

 ing the passage of the current. Electricity of feeble tension 

 passes through flame, because flame is an imperfect conductor; 

 but electricity of high tension forces a passage across heated 

 air, because the particles of the air are unable to resist its 

 powerful repulsive action. In the one case the presence of 



