Non-conducting Bodies in Electric Induction. 15 



by induction with negative and positive electricity, but you differ 

 from rue in respect to the explication of the experiment, in 

 respect, as you say, to the manner by which the disc has been 

 electrified, and the part which the flame has acted in the final 

 result. As to the first point, a mistake must have happened, 

 inasmuch as I have nowhere mentioned my view on the manner 

 by which the conducting and non-conducting bodies are excited 

 by induction. I fear that the word "distribution," whereby 

 the German word "Anordnung" (which signifies "arrange- 

 ment ") has been translated, has caused the mistake. It is said 

 (p. 412), "there is no essential difference between the actions 

 of conducting and non-conducting bodies, but inasmuch as the 

 distribution of electricity upon them," &c. ; and further, " in 

 conducting bodies the distribution of electricity," &c. {ibidem). 

 My meaning is this : It is admitted that each intermediate plate, 

 be it of conducting or of non-conducting matter, is by induc- 

 tion instantaneously provided with both electricities, which are 

 arranged in a certain manner upon both faces of the plate. 

 Upon a conducting plate I can specify by examination in every 

 case the arrangement of the electricities, and thereby accoimt 

 for the action of this plate upon a body in its vicinity and in- 

 duced by an electrified body. Upon a non-conducting plate I 

 cannot examine the arrangement of the electricities, but with a 

 presumed arrangement I can also account for the action of this 

 plate, and therefore I must deny an essential difference to be 

 between the action of conducting and non-conducting bodies in 

 electric induction*. That the manner whereby the induction 

 is produced upon a conducting and a non-conducting plate is 

 alike in every respect, I have neither said nor meant. 



As far as regards the result, indicated in my paper, of the ex- 

 periment with the flame, it is neither uncertain nor equivocal. 



* Supjiose a fluid insulating medium to exist between P and N instead of 

 air, ami the solid interposed plate np to have like insulating power and in- 

 ductive capacity as the medium, as for instance shell-lac in camphine or solid 

 sulphm' in melted sulphur, are we to expect the two electricities to appear 

 at the surfaces only of the solid plate, and not, as I suppose, in every pos- 

 sible section of either the fluid or the solid by planes, which, being ])arallel 

 to the surfaces of the plate, or rather perpendicular to the lines of induc- 

 tion, may be supposed to pass between the particles and mark their sepa- 

 ration one from the other ? Would not the first supposition be, to attri- 

 bute to insulating solids a power denied to insulating fluids, and would it 

 not also be equivalent to an admission that the solid could acquire a polar 

 state under induction which yet would be denied to its particles ? As the 

 phaenomenn of specific inductive capacity are now admitted, it is very de- 

 sirable that " the old theory " shoidd state how it accounts for them in 

 unexceiitionabie cases, as with sulphur or shell-lac ; and also explain how 

 a non-conducting plate can have the opposite electricities evolved and located 

 upon it* two surfaces without conduction ; or w ithout what I have called 

 polarization. — 51. F. 



