p 279 [286] lines 8 & 9. Not at all depending upon the manner in which it is excited except as that governs the quantity evolved. See remarks on identity1. May I suggest for "apparently" read "incidentally"2[.]
p 279 [286] line 15. "Rotation" merges in "Magnetic influence" being only a particular phenomenon of the latter.
Query Contact as an independent exciting cause. I am doubtful[.]
p 279 line 24 for "an" query "one"[.]
p 281 [287] line 1, 2 & 3 doubtful. Metals when insulated become very electric by friction agains[t] flannel &c &c[.] The want of effect generally is most likely due to the addition of conducting power not to a deficiency of exciting power[.]
p 282. [288] line 4, 5. Not so[.] Metals can be excited but being conductors they cannot retain their state if in communication with the earth. There are probably no non- electrics.
p 282 [289] at bottom[.] I think it very doubtful whether the attractions & repulsions can thus be referred directly & mechanically to the pressure of the air which is of course implied by pressure upon the air[.] I think Electricians have pursued the science here & given a clumsy mechanical view because they could not perceive a better[.]
p 285 [291-2] line 1. Harris of Plymouth I think denies this law. He has made many valuable expts recorded in the Plymouth Transactions3 but I have not had time to repeat & consider his results so as to give an opinion[.]
Page 285 [292] line 15. "Predicted". I do not remember that Mathematics have predicted much[.] Perhaps in Amperes theory one or at most two independent facts. I am doubtful of two. Facts have preceded the mathematics or where they have not the facts have remained unsuspected through the calculations were ready as in Electro-magnetic rotation & Magneto electricity generally and sometimes when the fact was present as in Aragos phenomenon4 the calculations were insufficient to illustrate its true nature until other facts came in to help[.]
Page 291 [298] line 20. Cavendish says Iron transmits 400,000,000 [times] better than water5 and I believe he is not far wrong[.]
Page 292 [300] line 6 for "for" ? "but"[.]
<-><-> line 20 for "attraction" ? "action" [.]
Page 293 line 6, 7. If insulated they become electric by friction[.]
<-> 294 [302] line 20. The action is not more intense upon one than upon another[.] Again line 27. The chemical action is not more intense it is uniform in all[.]
Page 296. [303] If the series be equally numerous large plates are more powerful than small plates[.] It does not require smallness in the plates to make numbers effective.
Page 298 [304-5] line 5, 6. Very doubtful[.] The heat is generally greatest in a decomposing solution at the Positive pole & least at the Negative for very simple reason namely the relative proportion removed by the oxygen & hydrogen &c &c &c[.]
Page 307. [316] The circumstances which determines whether it shall gain or lose being its position with respect to the magnetic equator & the higher or lower intensity of its previous magnetic state[.]
Page 315. [326] About 2/3 of a small magnet was immersed in mercury the lower end being fastened by a thread to the bottom &c &c.
Page 316 [326] line 4. "a wire touching the mercury". The action is between the magnet & wire not between the magnet & mercury.
<-><-> line 7. for "centrifugal" read "tangential"[.]
Page 317. for London University. He was first & is still of the R.I. and the Expt was first made at the R. Institution[.]
Page 326 [337] line 24. It is not from that experiment that I "infer" the action of a current in inducing another current[.] That result is proved by experiments without iron described in the 1st section of the "experimental researches"6[.] It merely requires that two copper wires should be placed by each other & a current sent from the battery through one for a reverse current instantly passes through the other[.]
Page 329 [341] line 8. Arago did not discover this source of electricity[.] He never suspected that it had anything to do with Electricity. For "Electricity" read "Magnetism" & then it will be right[.]
Page 330 [341] line 4. Dele[te] "confirm and" - it had been most abundantly confirmed[.]
Page 330 [342] line 8. <insert> "at certain points"
<-><-> line 27. for "flows" read "tends to flow"[.] It does not flow unless there be a communication between the two ends[.]
Page 331 [342] line 3. will "tend to" have a current &c &c[.]
<-><-> [342-3] <-> 7. of the radii "if a channel is open for their return and in a continuous plate that channel is afforded by the lateral portions" i.e of the portions on each side of the particular radius close to the Magnetic pole[.]
Dear Sir
I just wrote down at the moment whatever occurred to me. Do not therefore think me too free but treat these remarks just as freely
and oblige | Yours Very Truly | M. Faraday
Nov 1833
My best respects to Mrs Somerville
ARAGO, Dominique François Jean (1825): “L'action que les corps aimantés et ceux qui ne le sont pas exercent les uns sur les autres”, Ann. Chim., 28: 325-6.
CAVENDISH, Henry (1776): “An Account of some Attempts in imitate the Effects of the Torpedo by Electricity”, Phil. Trans., 66: 196-225.
FARADAY, Michael (1832a): “Experimental Researches in Electricity. On the Induction of Electric Currents. On the Evolution of Electricity from Magnetism. On a new Electrical Condition of Matter. On Arago's Magnetic Phenomena”, Phil. Trans., 122: 125-62.
FARADAY, Michael (1833a): “Experimental Researches in Electricity. - Third Series. Identity of Electricities derived from different sources. Relation by measure of common and voltaic Electricity”, Phil. Trans., 123: 23-54.
HARRIS, William Snow (1830): “Experimental Inquiries concerning the Laws of Electrical Accumulations”, Trans. Plymouth Inst., 45-97.
PATTERSON, Elizabeth Chambers (1983): Mary Somerville and the Cultivation of Science, 1815-1840, Boston.
SOMERVILLE, Mary (1834): On the Connexion of the Physical Sciences, London.
Please cite as “Faraday0684,” in Ɛpsilon: The Michael Faraday Collection accessed on 2 May 2024, https://epsilon.ac.uk/view/faraday/letters/Faraday0684