Answer to Dr. Harems Letter. 115 



a portion of matter with one electric force without the other, (see 

 par. 1177.) But if all this be true how can there be b. positively 

 excited particle? (See par. 1616.) Must not every particle be 

 excited negatively if it be excited positively ? Must it not have 

 a negative as well as a positive pole ?" Now I have not said ex- 

 actly what you attribute to me : my words are, " it is impossible 

 experimentally to charge a portion of matter with one electric 

 force independently of the other. Charge always implies induc- 

 tion, for it can in no instance be effected without," (1177.) I 

 can however easily perceive how my words have conveyed a 

 very different meaning 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 with- 

 out the other, that body being considered in relation to itself 

 only. But I think that such charge cannot exist without induc- 

 tion, (1178,) or independently of what is called the development 

 of an equal amount of the other electric force, not in itself, but 

 in the neighboring consecutive particles of the surrounding die- 

 lectric, and through them of the facing particles of the uninsu- 

 lated surrounding conducting bodies; which, under the circum- 

 stances 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 A, B, C, of iv, v, vi, vii, fully 

 illustrate my views, (1672.) 



xxviii. The third paragraph of page 6, includes the question, 

 " is tliis consistent?" implying self-contradiction, which therefore 

 I proceed to notice. The question arises out of the possibility of 

 glass being a (slow) conductor or not of electricity ; a point ques- 

 tioned also in the two preceding paragraphs. I believe that it is. 

 I have charged small Ley den jars, made of thin flint glass tube, 

 with electricity, taken out the charging wires, sealed them up 

 hermetically, and after two or three years have opened and found 

 no charge in them. I will refer you also to Belli's curious ex- 

 periments upon the successive charges of a jar, and the successive 

 return of portions of these charges.* I will also refer to the 

 experiments with the shell lac hemisphere, especially that de- 

 scribed in 1237 of my researches : also the experiment in 1246. 



* Bibliotheca Italiana, 1837, Lxxxv, p. 417. 



