Ansar ai2De: BardGMiter 119 
and that in both cases the effects are consistent with my theory 
of induction. 
_ xxxvii. I now come to what may be eabideind as queries in 
your letter, which I ought to answer. The second paragraph 
page 3isone. 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. 
xxxvill. 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, 1672, 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 polarity is so diverse when applied 
to light, to a crystal, to a magnet, to the voltaic battery, and so 
different 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 
city. The next or fourth par. of page 3, involves a vimana 
of my views. Ido 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, (xxxviil. 
xl. And now, my dear sir, I think I onght to din my reply 
toan 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, 
