54 Prof. Faraday's Answer to Dr. Hare's Letter 



any hypothesis which I could imagine. How are we to ex- 

 plain the insensibility of a gold-leaf electroscope, to a galvan- 

 ized wire, or the indifference of a magnetic needle to the most 

 intensely electrified surfaces ? 



38. Possibly the Franklinian hypothesis may be combined 

 with that above suggested, so that an electrical current may 

 be constituted of an imponderable fluid in a state of polariza- 

 tion, the two electricities being the consequence of the posi- 

 tion of the poles, or their presentation. Positive electricity 

 may be the result of an accumulation of electric particles, pre- 

 senting poles of one kind ; negative, from a like accumulation 

 of the same matter with a presentation of the opposite poles, 

 inducing of course an opposite polarity. The condensation 

 of the electric matter, within ponderable matter, may vary 

 in obedience to a property analogous to that which deter- 

 mines the capacity for heat, and the different influence of 

 dielectrics upon the process of electrical induction may arise 

 from this source of variation. 



With the highest esteem, I am yours truly, 



ROBERT HARE. 



An Answer to Dr. Hare's Letter on certain Theoretical 

 Opinions. By M. FARADAY. 



MY DEAR SIR, 



i. VTOUR kind remarks have caused me very carefully to re- 

 * vise the general principles of the view of static induction 

 which lhave ventured to put forth, with the very natural fear 

 that as it did not obtain your acceptance, it might be founded 

 in error ; for it is not a mere complimentary expression when 

 I say I have very great respect for your judgement. As the 

 reconsideration of them has not made me aware that they 

 differ amongst themselves or with facts, the resulting im- 

 pression on my mind is, that I must haveexpressed my meaning 

 imperfectly, and I have a hope that when more clearly stated 

 my words may gain your approbation. I feel that many of 

 the words in the language of electrical science possess much 

 meaning ; and yet their interpretation by different philoso- 

 phers often varies more or less, so that they do not carry 

 exactly the same idea to the minds of different men : this often 

 renders it difficult, when such words force themselves into use, 

 to express with brevity as much as, and no more than, one 

 really wishes to say. 



ii. My theory of induction (as set forth in Series xi. xii. 

 and xiii.) makes no assertion as to the nature of electricity, or 

 at all questions any of the theories respecting that subject 



