Summary : Nature of Inductive Action. 427 



force equivalent to a dilatation or repulsion of these repre- 

 sentative lines (1224.); or the attractive force which exists 

 amongst the particles of the dielectric in the direction of the 

 induction is accompanied by a repulsive or a diverging force 

 in the transverse direction (1304.). 



1298. Induction appears to consist in a certain polarized 

 state of the particles, into which they are thrown by the elec- 

 trified body sustaining the action, the particles assuming po- 

 sitive and negative points or parts, which are symmetrically 

 arranged with respect to each other and the inducting sur- 

 faces or particles*. The state must be a forced one, for it is 

 originated and sustained only by force, and sinks to the 

 normal or quiescent state when that force is removed. It can 

 be conti7iued only in insulators by the same portion of electri- 

 city, because they only can retain this state of the particles 

 (1304.). 



1299. The principle of induction is of the utmost gene- 

 rality in electric action. It constitutes charge in every or- 

 dinary case, and probably in every case ; it appears to be the 

 cause of all excitement, and to precede every current. The 

 degree to which the particles are affected in this their forced 

 state, before discharge of one kind or another supervenes, 

 appears to constitute what we call intensity. 



1300. When a Leyden jar is charged^ the particles of the 

 glass are forced into this polarized and constrained condition 

 by the electricity of the charging apparatus. Discharge is 

 the return of these particles to their natural state from their 

 state of tension, whenever the two electric forces are allowed 

 to be disposed of in some other direction. 



1301. All charge of conductors is on their surface, because 

 being essentially inductive, it is there only that the medium 

 capable of sustaining the necessary inductive state begins. If 

 the conductors are hollow and contain air or any other di- 

 electric, still no charge can appear upon that internal surface, 

 because the dielectric there cannot assume the polarized state 

 throughout, in consequence of the opposing actions in different 

 directions. 



1302. The known influence o^ form is perfectly consistent 

 with the corpuscular view of induction set forth. An elec- 

 trified cylinder is more affected by the influence of the sur^ 

 rounding conductors (which complete the condition of charge) 

 at the ends than at the middle, because the ends are exposed 



* The theory of induction which I am stating does not pretend to de- 

 cide whether electricity be a fluid or fluids, or a mere power or condition 

 of recognised matter. That is a question which I may be induced to con- 

 sider in the next or following series of these researches. 



