upon the Electricity of Flame. 547 



however, the wick was raised by degrees, and the flame by this 

 means increased, the needle receded more and more towards Oj 

 and by continually increasing the flame, was caused to cross to 

 the negative side. In this case, therefore, the current of the 

 single copper and zinc element overcame that of the flame, 

 although both had to contend with the same amount of resist- 

 ance. This change in the direction of the needle must therefore 

 be referred to a change in the electro-motive force which origi- 

 nates the current. As the zinc and copper have remained un- 

 changed, the cause of the phsenomenon must be sought in a di- 

 minution of the electro-motive force of the flame. This diminu- 

 tion is without doubt due to the fact, that the flame when thus 

 increased acts against the inner surface of the chimney so as to 

 originate a number of conducting threads of flame between the 

 chimney and the platinum, which, owing to their shortness and 

 position in the flame, possess a greater power of conduction, but 

 a less tension at their extremities, than that existing between 

 the top and bottom of the flame. That the resistance to con- 

 duction in this state of the flame is very much decreased, may 

 be inferred from the magnitude of the negative angle. Even 

 this reversion of the angle could be brought about with a single 

 element when the chimney was removed, and a piece of platinum 

 was pushed sideways into the flame at a greater or less distance 

 above the wick, and then connected with the lamp ; for in this 

 case also the electric difference between the respective portions 

 of the flame which encompassed both pieces of platinum was less 

 than the difi'erence between the top and bottom of the flame. 

 When a platinum wire, which was smelted into a thin glass tube, 

 was introduced into the flame, and when the plate of platinum was 

 held a little above it, both being connected with the wires of the 

 galvanometer (the lamp was not in the circuit), an angle of 15° 

 was observed. By directing the current of the zinc and copper 

 element against this, the needle was brought down and set on 

 the negative side. When the flame was diminished until its 

 luminous point reached merely to the summit of the chimney, 

 the flame-current gave an angle of 20° ; which increase was cer- 

 tainly due, not to an increase of conductibility, but to a higher 

 tension. The opposition of the zinc and copper element reduced 

 this angle only to 14°. 



These experiments furnish a convincing proof that the flame 

 itself is the birth-place of an electric current ; for if it merely 

 played the part of a conductor, then an increase in the conducti- 

 bility of a certain portion of the circuit could not cause the needle 

 to pass from the positive to the negative position. 



The experiments prove further, that between the different 

 portions of the flame the powers of conduction, as also the elec- 



