396 Dr. Faraday's Researches in Electricity. [Series xx. 



not such as to render the following reductions of merely theo- 

 retical interest, we may develope the formulas for t, y*, and 

 such other symbols as may be requisite, so as to render the 

 operations uniform and comparatively easy. The reductions 

 I allude to, all of which are in theory possible f» are those of 

 / 3 (3.2 m -2) toh^ + h^ + . + hl 



/ 4 ( Mw )toV + V + - + 'C> 



/> m )toV+y+.+^, 



where h r is, in general, a linear though not homogeneous 

 function of m — r + 1 undetermined quantities, 



u x+l = 3.2 2 % +1 -2; ^ +1 = 3.2 2 "*-1; u = v =l; 



andy a (b) denotes the general function of the ath degree and 

 bih order J, according to the notation which I used at p. 126 

 of the last volume. 



Devereux Court, March 31, 1846. 



LXVI. Experimental Researches in Electricity. — Twentieth 

 Series. By Michael Faraday, Esq., D.C.L., F.R.S., 

 Fullerian Prof. Chem. Royal Institution, Foreign Associate 

 of the Acad. Sciences, Paris, Cor. Memb. Royal and Imp. 

 Acadd. of Sciences, Petershirgh, Florence, Copenhagen, 

 Berlin, Gottingen, Modena, Stockholm, fyc. #c.§ 



§ 27. On new magnetic actions, and on the magnetic condi~ 

 tion of all matter || . 



\\. Apparatus required. ^[ ii. Action of magnets on heavy glass. 

 ^[ iii. Action of magnets on other substances acting magnetically 

 on light. % iv. Action of magnets on the metals generally. 



2243. HPHE contents of the last series of these researches 



■* were, I think, sufficient to justify the statement, 



that a new magnetic condition (i. e. one new to our know- 



* Sup. p. 190. See also one of mv previous papers in the Phil. Mag. 

 S. 3. vol. xxvii. pp. 292, 293. 



f See Mathematician, vol. ii. p. 97. Ex. xlix. for a discussion of the 

 first reduction. 



\ The order being the number of undetermined quantities, the degree 

 the dimensions to which they enter. Might not the term 'simple' be ad- 

 vantageously applied to all equations of the first order? 



§ From the Philosophical Transactions for 184G, Part I., having been 

 read December 18, 1845. 



|| My friend Mr. Wheatstone has this day called my attention to a paper 

 by M. Becquerel, " On the magnetic actions excited in all bodies by the 

 influence of very energetic magnets," read to the Academy of Sciences on 

 the 27th of September 1827, and published in the Annates de Chimie,xxxvi. 

 p. 337. It relates to the action of the magnet on a magnetic needle, on 



