162 DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XIII.) 



Whether the application of heat were by a flame applied underneath, or one directed 

 by a blow pipe from above, or by a hot iron or coal, the effect was the same. 



1640. Having thus removed the difficulty out of the way of my views regarding a 

 current, I did not pursue this curious experiment further. It is probable, that the 

 difference between my results and those of M. de la Rive may depend upon the re- 

 lative values of the currents used ; for I employed only a weak one resulting from two 

 pairs of plates two inches long and half an inch wide, whilst M. de la Rive used four 

 pairs of plates of sixteen square inches in surface. 



1641. Electric discharges in the atmosphere in the form of balls of fire have occa- 

 sionally been described. Such phenomena appear to me to be incompatible with all 

 that we know of electricity and its modes of discharge. As time is an element in 

 the effect (1418. 1436.) it is possible perhaps that an electric discharge might really 

 pass as a ball from place to place ; but as every thing shows that its velocity must be 

 almost infinite, and the time of its duration exceedingly small, it is impossible that 

 the eye should perceive it as anything else than a line of light. That phenomena of 

 balls of fire may appear in the atmosphere, I do not mean to deny; but that they have 

 anything to do with the discharge of ordinary electricity, or are at all related to 

 lightning or atmospheric electricity, is much more than doubtful. 



1642. All these considerations,, and many others, help to confirm the conclusion, 

 drawn over and over again, that the current is an indivisible thing; an axis of power, 

 in every part of which both electric forces are present in equal amount* (517- 1627.)- 

 With conduction and electrolyzation, and even discharge by spark, such a view will 

 harmonize without hurting any of our preconceived notions ; but as relates to con- 

 vection, a more startling result appears, which must therefore be considered. 



1643. If two balls A and B be electrified in opposite states and held within each 

 other's influence, the moment they move towards each other, a current, or those 

 effects which are understood by the word current, will be produced. Whether A move 

 towards B, or B move in the opposite direction towards A, a current, and in both 

 cases having the same direction, will result. If A and B move from each other, then 

 a current in the opposite direction, or equivalent effects, will be produced. 



1644. Or, as charge exists only by induction (1178. 1299.), and a body when elec- 

 trified is necessarily in relation to other bodies in the opposite state ; so, if a ball be 

 electrified positively in the middle of a room and be then moved in any direction, 

 effects will be produced, as if a current in the same direction (to use the conventional 



* I am glad to refer here to the results obtained by Mr. Christie with magneto-electricity, Philosophical 

 Transactions, 1833, p. 113. note. As regards the current in a wire, they confirm everything that I am con- 

 tending for. 



