Rectilinear Electrical Current on itself, 143 



whenever in your experiments you have observed a true attrac- 

 tion at a distance, the two parts of your conductor were neces- 

 sarily disjoined; that is to say, there could be no current other 

 than that which is propagated by the sparks ; and you will 

 agree with us that every spark indicates a marked difference in 

 the electrical condition of the two surfaces between which it 

 springs, a difference which ought necessarily to produce an 

 attraction between the two. The current transmitted by these 

 sparks is always too feeble, in too small quantity, as would 

 formerly have been said, to produce any appreciable mechanical 

 effect. But in making contact between the two portions of your 

 conductor, there was certainly a current; an attraction at a 

 distance could not be perceived, but instead of it you have seen 

 an adhesion which lasted some time after the current had been 

 broken. Could not this persistence be an indication that this 

 adhesion is not a direct effect of the current (the rupture of 

 which ought to stop it instantaneously), but is a secondary effect ? 

 We think so. In our opinion the explanation of the pheno- 

 menon is as follows. 



As soon as the current is closed, the moveable current is re- 

 pelled. It only, however, moves to a slight distance, which can- 

 not be otherwise, seeing that the force of repulsion, not very 

 great itself, must overcome that of torsion while only acting 

 during an excessively short time, and on a relatively consider- 

 able mass. It would go further than it does, if at the same 

 moment that it quits the conductor an induction spark, a small 

 voltaic arc, did not instantaneously pass between the two. This 

 arc, as is always the case when it springs between two fusible elec- 

 trodes placed at a very small distance, is almost entirely composed 

 of a kind of melted metal. It is broken after a very short exist- 

 ence; but the rupture of the circuit brings about a new induc- 

 tion with its arc, which also quickly breaks, and so on. You 

 have often heard these sparks : this is the fizzing noise of which 

 you speak. The interposition of an induction-coil in the circuit, 

 which, as you found, promotes the success of your experi- 

 ments, does so only by giving rise to stronger sparks. Without 

 that its effect would be absolutely inexplicable, for its presence 

 can only weaken the continuous current. And further, if you 

 still possess the conductors which you have used in your experi- 

 ments, be good enough to examine, through a lens, the ends by 

 which they touched ; you will readily see the traces, the relics, so 

 to speak, of the melted wire of which we have spoken. This 

 wire prevents the two conductors from removing too far from 

 each other, just as a very small drop of liquid adhering to their 

 surfaces would, if introduced between the two. After the rupture 

 of the circuit, it solidifies instantaneously and keeps them soldered 



