upon the Electricity of Flame. 545 



and this was also the case when aether was added^ which boiled 

 during its combustion. 



When instead of the platinum crucible an iron vessel of some- 

 what similar shape was used^ on igniting the aether therein con- 

 tained an angle only half the size of that with the platinum cru- 

 cible was observed. 



When sheet-iron or a plate of zinc was substituted for the 

 platinum foil which was held in the flame, the current was 

 weaker. With iron it was about four-fifths, with zinc about two- 

 thirds of its amount with the platinum. This was equally true, 

 whether the aether burnt in the platinum crucible or in the iron 

 vessel ; in the latter case the diminution was proportionate. 



To exhibit the current, it is not necessary to introduce metal 

 into the flame ; the same can be effected by bringing the moist 

 hand into it, or what is more convenient, a strip of paper satu- 

 rated with moisture. When, for instance, one end of the wire 

 was connected with the lamp, the other end being held in one 

 of my hands or in my mouth, the current could be developed in 

 die manner described. As was natural to expect, a less angle 

 was observed in the present case. 



The magnitude of the resistance offered by the flame, in com- 

 parison with the not inconsiderable resistance of the 16,454 feet 

 of exterior wire, is exhibited in the following experiments. The 

 lamp No. 1 alone with the piece of platinum held in the flame 

 above it, gave an angle of 8°'3. The lamp No. 2 with its plate 

 of platinum gave an angle of 3°'8 -, and the lamp No. 3 with 

 its platinum gave a considerably less angle. When the lamps 

 No. 1 and No. 2 were placed one after the other like a galvanic 

 battery, the angle was 8°-4 ; and when all three were used in 

 this manner, the angle was only 2°*7. When, however, the 

 lamps 1 and 2 were both connected with one end of the wire of 

 the galvanometer, while the two pieces of platinum foil placed 

 over their flames were connected with the other end, an angle of 

 10°*3 was obtained; and when all three lamps were used, the 

 angle amounted to 11°* 7*. 



* It is perhaps worth remarking, that the two arrangements of the lamps 

 liere spoken of correspond to two distinct arrangements of the galvanic 

 battery ; the first being used when an exterior resistance is to be overcome, 

 the second w^hen the resistance within the cells is to be diminished. Let^ 

 be the strength of the current exhibited, e the electro-motive force, n the 

 number of cells, R the resistance within them, r the resistance without them; 



in the former arrangement p would be expressed by the formula p^= , 



while in the latter ai-rangement we should have the formula »=— 



The above experiments therefore show that the resistance of the flame itself 

 is great in comparison to the resistance of the exterior wire- — T. 



