60 Prof. Faraday's Answer to Dr. Hare's Letter 



first refers to an agent which is represented by the idea of 

 one imponderable fluid, the second to an agency better repre- 

 sented probably by the idea of two fluids, or at least by two 

 forces: the first involves no polar action, nor any of its con- 

 sequences, the second depends essentially on such actions ; 

 with the first, if a certain portion be originally employed in 

 the centre of a spherical arrangement, but a small part appears 

 ultimately at the surface; with the second, an amount of force 

 appears instantly at the surface (viii. ix. x. xi. xii. xiii. xiv.) 

 exactly equal to the exciting or moving force, which is still at 

 the centre. 



xxvi. Paragraph 13 involves another charge of self-contra- 

 diction, from which, therefore, I will next endeavour to set 

 myself free. You say I "correctly allege that it is impossible 

 to charge a portion of matter with one electric force without 

 the other (see par. 1177). But if all this be true, how can 

 there be a. positively excited particle"! (see par. 1616). Must 

 not every particle be excited negatively if it be excited posi- 

 tively? Must it not have a negative as well as a positive 

 pole?" Now I have not said exactly what you attribute to 

 me ; my words are, " it is impossible, experimentally, to 

 charge a portion of matter with one electric force independ- 

 ently of the other: charge always implies induction, for it 

 can in no instance be effected without (1 177.)." I can, how- 

 ever, easily perceive how my words have conveyed a very 

 different idea to your mind, and probably to others, than that 

 I meant to express. 



xxvii. Using the word charge in its simplest meaning (iii. 

 iv.), I think that a body can be charged with one electric 

 force without the other, that body being considered in rela- 

 tion to itself only. But I think that such charge cannot exist 

 without induction (1178.), or independently of what is called 

 the development of an equal amount of the other electric 

 force, not in itself, but in the neighbouring consecutive par- 

 ticles of the surrounding dielectric, and through them of the 

 facing particles of the uninsulated surrounding conducting 

 bodies, which, under the circumstances, terminate as it were 

 the particular case of induction. I have no idea, therefore, 

 that a particle when charged must itself of necessity be polar ; 

 the spheres ABC of iv., v., vi., vii., fully illustrate my views 

 (1672.). 



xxviii. Paragraph 20 includes the question, "is this con- 

 sistent?" implying self-contradiction, which, therefore, I 

 proceed to notice. The question arises out of the pos- 

 sibility of glass being a (slow) conductor or not of electri- 

 city, a point questioned also in the two preceding para- 



