2 Second Letier from Dr. Hare to Prof. Faraday. 
‘aware that when in a discussion, which due attention to brevity 
must render unceremonious, diversities of opinion are exhibite 
much magnanimity is requisite in the party whose opinions are 
assailed ; but I trust that both of us have truth in view above all © 
other objects, and that so much of your new doctrine as tends to 
promote that end, will not be invalidated by a criticism which 
though free, is intended to be perfectly fair and friendly. ~ 
In paragraph (ii,) your language is as follows, “my theory of 
induction makes no assertion as to the nature of electricity, nor 
at all questions any of the theories respecting that subject.” Ow- ~ 
ing to this avowed omission to state your o of the nature — 
of electricity as preliminary to the statement of your “theory,” — 
c was unable to reconcile that theory with those pre- 
viously accredited, I received the impression that you claimed no 
aid from any imponderable principle. It appeared to me that 
_ there was no room for the agency of any such principle, if induc- 
tion were an action of contiguous ponderable particles, consisting 
of aspecies of polarity. It seemed to follow, that what we call 
electricity, could be nothing more than a polarity, in the ponder- 
able particles, directly caused by those mechanical or chemical 
frictions, movements, or reactions by which ponderable bodies 
are electrified. You have correctly inferred that I had not seen 
the fourteenth series of your researches, containing certain para- 
graphs. From them it appears that the polarity, on which so ‘ 
much stress has been laid, is analogous to that which haslong 
been known to arise in a mass, about which the electric equilibri- 
um has been subverted, by the inductive influence of the electri- _ 
city accumulated upon another mass. ‘This is clearly explained 
in paragraph iv of your letter, by the illustration, agreeably to 
which three bodies, A, B, ©, are situated in a line, in the order in ~ 
_ which they are named, in proximity, but not in contact. “Ais — j 
electrified positively and then C is uninsulated.” It is evident 
that you are correct in representing that under these circumstan- 
ces the extremities of B will be oppositely excited, so as to have — 
_ @reaction with any similarly excited body, analogous to that 
uch takes place between magnets ; since the similarly excited 
* 
o 
‘a 
ne ‘extremities of two such bodies, would repel each other; while 
those dissimilarly excited, would be reciprocally attractive. Hence ‘i 
_ no doubt the word polarity is conceived by you to convey an idea 
If I may be allowed to propose an | 
ro 
of the state of the body B. 
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- ae. Be gee aE ° ee 
