Answer to Dr. Hare's Letter. 119 



and that in both cases the effects are consistent with my theory 

 of induction. 



xxxvii. I now come to what may be considered as queries in 

 your letter, which I ought to answer. The second paragraph 

 page 3 is one. As I concede that particles on opposite sides of a 

 vacuum may perhaps act on each other, you ask " wherefore is 

 the received theory of the mode in which the excited surface of 

 a Leyden jar induces in the opposite surface a contrary state, ob- 

 jectionable ?" My reasons for thinking the excited surface does 

 not directly induce upon the opposite surface, &c. is first, my be- 

 lief that the glass consists of particles, conductors in themselves 

 but insulated as respects each other (xvii) ; and next that in the 

 arrangement given iv, ix or x, A does not induce directly on C 

 but through the intermediate masses or particles of conducting 

 matter. 



xxxviii. In the next paragraph the question is rather implied 

 than asked, what do I mean by polarity ? I had hoped that the 

 paragraphs 1669, 1670, 1671, 1673, 1679, 1686, 1687, 1688, 

 1699, 1700, 1701, 1702, 1703, 1704, in the researches would 

 have been sufficient to convey my meaning, and I am inclined 

 to think you had not perhaps seen them when your letter was 

 written. They, and the observations already made (v, xxvi), 

 with the case given (iv, v), will I think be sufficient as my an- 

 swer. The sense of the word, polariti/ is so diverse when applied 

 to light, to a crystal, to a magnet, to the voltaic battery, and so 

 difierent in all these cases to that of the word when applied to 

 the state of a conductor under induction (v), that I thought it 

 safer to use the phrase " species of polarity" than any other which, 

 being more expressive, would pledge me farther than I wished 

 to go. 



xxxix. The next or fourth par. of page 3, involves a mistake 

 of my views. I do not consider bodies which are charged by 

 friction or otherwise as polarized, or as having their particles po- 

 larized (iii, iv, xxvii). This paragraph and the next do not re- 

 quire therefore any further remark, especially after what I have 

 said of polarity above, (xxxviii. ) 



xl. And now, my dear sir, I think I ought to draw my reply 

 to an end. The paragraphs which remain unanswered, refer, 1 

 think, only to differences of opinion, or else not even to differen- 

 ces, but opinions regarding which I have not ventured to judge. 



