Franklin, Dufay a7id Ampere. 467 



same intensity, and consequently, in any given time, fall to 

 the earth through the same perpendicular distance, whether 

 moving with the celerity of a cannon-ball, or undergoing no 

 im})ulse excepting those arising from their own unresisted 

 weights. 



20. The objections which are thus shown to be applicable 

 in the case of liquids, of which the neighbouring particles are 

 destitute of the reaction requisite to produce the phsenomena 

 requiring explanatioHj must operate with still greater force 

 where aethereal fluids are in question, of which the properties 

 are positively irreconcileable with the phaenomena. According 

 both to Franklin and Dufay, bodies, when similarly electrified, 

 should repel each other; yet in point of fact, collateral wires, 

 when subjected to similar voltaic discharges, and of course 

 similarly electrified, become reciprocally attractive, while 

 such wires, when dissimilarly electrified by currents which 

 are not analogous, become reciprocally repulsive. 



21. Agreeably to Ampere, an iron bar, situated within a 

 coil of wire subjected to a galvanic current, is magnetized, 

 because the current in the wire is productive of an electrical 

 whirlpool about every particle of the metal. When the iron 

 is soft, the magnetism, and of course the gyrations of which 

 its magnetism consists by the premises, cease for the most 

 part as soon as the circuit through the coil is broken; but 

 when the iron is in the more rigid state of hardened steel, the 

 gyrations continue for any length of time after the exciting 

 cause has ceased. 



22. This theory does not explain wherefore the hardening 

 of the steel should cause the gyration to be more difficult to 

 induce yet more lasting when its induction is effected. Evi- 

 dently the metallic particles must take some part in the pro- 

 cess; since it is dependent for its existence and endurance 

 upon their nature and their state. Yet no function is assigned 

 to these particles. In fact, it is inconceivable, either that 

 they can participate in, or contribute to, the supposed gyration. 



23. The electrical fluid in an iron bar cannot form a vortex 

 about each |)article, all the vortices turning in one direction, 

 without a conflict between those which are contiguous. In 

 order not to conflict with each other, the alternate vortices 

 would have to turn in different directions, like interlocking 

 cog-wheels in machinery. But in that case, if magnetism be 

 due to currents, the magneto-inductive influence of one set 

 would neutralize that of the other. Again, how can a current, 

 excited by a battery in one circuitous conductor, cause, by 

 dynamic induction, a current in the opi)Osite directio7i, through 

 another conductor parallel to the 'first, but insulated there- 



2 H 2 



