AGiter t-Di. Hates Lama. 117 
charge; any one of which may cause the discharge of the jar, or 
the discharge of the inductive arrangements described in this 
letter (xxx); the action of the particles in any one of these cases 
being entirely different from the mere return action of the polari- 
zed particles of the glass of the jar, or the polarized globe B (v) 
to their first state. My view of the relation of insulators and con- 
ductors, as bodies of one class, is given at 1320, 1675, &c. of the 
researches ; but I do not think the particles of the good conduc- 
tors acquire an intensity of polarization any thing like that of the 
particles of bad conductors, on the contrary I conceive that the 
contiguous polarized particles (1670) of good conductors discharge 
to each other when their polarity is at a very low degree of in- 
tensity, (1326, 1338, 1675.) The question of, why are the me- 
tallic particles dissipated when the charge is sufficiently powerful— 
is one that my theory is not called upon at present to answer ; 
since it will be acknowledged by all that the dissipation is not 
necessary to discharge ; that different effects ensue upon the sub- 
jection of bodies to different degrees of the same power is com- 
mon enough in experimental philosophy: thus one degree of heat 
will merely make water hot whilst a higher will aces it as 
steam and a lower will convert it into ice. 
xxxii. The next most important point, as it appears to me, is 
that contained in the third and fourth paragraphs of page 5. I 
have said, (1330,) “what, then, is to separate the principle of 
these two extremes, perfect conduction and perfect insulation, 
from each other ; since the moment we leave in the smallest de- 
gree perfection at either extremity we involve the element of per- 
fection at the opposite end ?”-and upon this you say, might not 
this query be made with as much reason in the case of motion 
and rest ?—and, in any case of the intermixture of opposite quali- 
ties may it not be said, the moment we leave the element of per- 
fection at one end, we involve the element of perfection at the 
opposite? may it not be said of light and darkness, or of opaque- 
ness and translucency? and so forth. 
_ xxxiii. I admit that these questions are very properly put, not 
that I go to the full extent of them all, as for instance that of 
motion and rest, but Ido not perceive their bearing upon the 
question of whether conduction and insulation are different prop- 
erties dependent upon two different modes of action of the par- 
ticles of the substances, respectively possessing these actions ; or 
