116 Answer to Dr. Hare’s Letter. 
I cannot conceive how in these cases the air in the vicinity of 
the coating could gradually relinquish to it a portion of free elec- 
' tricity conveyed into it by what I call convection, since in the 
first experiment quoted (1237), when the return was gradual, 
there was no coating ; and in the second (1246) when there was 
a coating, the return action was most sudden and instantaneous. 
xxix. Par. 4 of page 6, and par. 1 of page 7, perhaps only re- 
quire a few words of explanation. In a charged Leyden jar, I 
have considered the two opposite forces in the inductrie and in- 
ducteous surfaces, as being directed towards each other through 
the glass of the jar, provided the jar have no projection of its 
inner coating and is uninsulated on the outside, (1682.) When 
discharged by a wire, or discharger, or any other of the many 
arrangements used for that purpose, is made, these supply the 
“some other directions” spoken of, (1682, 1683.)- 
xxx. The inquiry in par. 2 of page 7, I should answer, by say- 
ing, that the process is the same as that by which the polarity of 
the sphere B, (iv, v,) would be neutralized, if the spheres A and 
C were made to communicate by a metallic wire; or that by 
which the 100 or 1000 intermediate spheres (x), or the myriads 
of polarized conducting particles (xi), would be discharged, if the 
inner sphere A and the outer one C were brought into communi- 
cation by an insulated wire ; a circumstance which would not 
in the least affect the posdision of abe. joyeren ee: exterior of 
the globe C. 
xxxi. The obscurity i in my papers se hat led fo aaa re- 
marks in par. 1, page 8, arises, as it appears to me, (after my own 
imperfect expression, ) fine the uncertain or double meaning of 
the word discharge. You say, “if discharge involves a return 
to the same state in vitreous particles, the same must be true in 
those of the metallic wire ; wherefore then are these dissipated 
when the discharge is sufficiently powerful?” A jar is said to 
be discharged when its. charged state is reduced by any means, 
and it is found in its first indifferent condition ; the word is then 
used simply to express the state of the apparnitié, and so I have 
used it in the expressions criticised in par. 4 of page 6 already — 
referred to. The process of discharge, or the mode by which 
the jar is brought into the discharged state, may be subdivided 
as. of various kinds; and I have spoken of conductive (1320); 
electrolytic (1343), disruptive (1359), and convective (1562) dis- 
