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II. Experimental Researches in Electricity . — Twentieth Series. 
By Michael Faraday, Esq., D.C.L. F.R.S., Fullerian Prof. Chem. Royal Institu- 
tion, Foreign Associate of the Acad. Sciences, Paris, Cor. Memh. Royal and Imp. 
Acadd. of Sciences, Peter shurgh, Florence, Copenhagen, Berlin, Gottingen, Modena, 
Stockholm, 8$c. Sfc. 
Received December 6, — Read December 18, 1845. 
§ 2 7- On new magnetic actions, and on the magnetic condition of all matter*. 
^ i. 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. The 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- 
ledge) had been impressed on matter by subjecting it to the action of magnetic 
and electric forces (222 7.) ; which new condition was made manifest by the powers 
of action which the matter had acquired over light. The phenomena now to be 
described are altogether different in their nature ; and they prove, not only a mag- 
netic condition of the substances referred to unknown to us before, but also of many 
* 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 Annales de Chimie, xxxvi. p. 337. It relates 
to the action of the magnet on a magnetic needle, on soft iron, on the deutoxide and tritoxide of iron, on the 
tritoxide alone, and on a needle of wood. The author observed, and quotes Coulomb as having also observed, 
that a needle of wood, under certain conditions, pointed across the magnetic curves ; and he also states the 
striking fact that he had found a needle of wood place itself parallel to the wires of a galvanometer. These 
effects, however, he refers to a degree of magnetism less than that of the tritoxide of iron, but the same in 
character, for the bodies take the same position. The polarity of steel and iron is stated to be in the direction 
of the length of the substance, but that of tritoxide of iron, wood and gum-lac, most frequently in the direction 
of the width, and always when one magnetic pole is employed. “ This difference of effect, which establishes a 
line of demarcation between these two species of phenomena, is due to this, that the magnetism being very 
feeble in the tritoxide of iron, wood, &c., we may neglect the reaction of the body on itself, and therefore the 
direct action of the bar ought to overrule it.” 
As the paper does not refer the phenomena of wood and gum-lac to an elementary repulsive action, nor show 
that they are common to an immense class of bodies, nor distinguish this class, which I have called diamagnetic, 
from the magnetic class ; and, as it makes all magnetic action of one kind, whereas I show that there are two 
kinds of such action, as distinct from each other as positive and negative electric action are in their way, so I 
do not think I need alter a word or the date of that which I have written ; but am most glad here to acknow- 
ledge M. Becquerel’s important facts and labours in reference to this subject. — M. F. Dec. 5, 1845. 
