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III. Experimental Researches in Electricity. — Twenty-sixth Series. By Michael 
Faraday, Esq., D.C.L., F.R.S., Fullerian Prof. Chem. Royal Institution, Foreign 
Associate of the Acad. Sciences, Paris, Ord. Boruss. Pour le Mdrite, Eq., Memb. 
Royal and Imp. Acadd. of Sciences, Petershurgh, Florence, Copenhagen, Berlin, 
Gottingen, Modena, Stockholm, Munich, Bruxelles, Vienna, Bologna, 8^c. S^c. 
Received October 9*, — Read November 28, 1850. 
^ 32. Magnetic conducting power. § 33. Atmospheric magnetism. 
^ i. Magnetic conduction. ^ ii. Conduction polarity . ^ iii. Magnecrystallic con- 
duction. ^ 33. Atmospheric magnetism. ^ i. General Principles.. 
^ i. Magnetic conduction. 
2797 . XhE remarkable results given in a former series of these researches &c.) 
respecting the powerful tendency of certain gaseous substances to proceed either to 
or from the central line of magnetic force, according to their relation to other sub- 
stances present at the same time, and yet the absence of all condensation or expan- 
sion of these bodies (2756.) which might be supposed to be consequent on such an 
amount of attractive or repulsive force as would be thought needful to produce this 
tendency and determination to particular places, have, upon consideration, led me 
to the idea, that if bodies possess different degrees of conducting power iov magnetism, 
that difference may account for all the phenomena; and, further, that if such an idea 
be considered, it may assist in developing the nature of magnetic force. I shall 
therefore venture to think and speak freely on this matter for a while, for the purpose 
of drawing others into a consideration of the subject ; though I run the risk, in doing 
so, of falling into error through imperfect experiments and reasoning. As yet, how- 
ever, I only state the case hypothetically, and use the phrase conducting power as a 
general expression of the capability which bodies may possess of affecting the trans- 
mission of magnetic force ; implying nothing as to how the process of conduction is 
carried on. Thus limited in sense, the phrase may be very useful, enabling us to 
take, for a time, a connected, consistent and general view of a large class of pheno- 
mena ; may serve as a standard of meaning amongst them, and yet need not neces- 
sarily involve any error, inasmuch as whatever may be the principles and condition 
of conduction, the phenomena dependent on it must consist among themselves. 
2798. If a medium having a certain conducting power occupy the magnetic field, 
and then a portion of another medium or substance be placed in the field having 
* Revised by the author and returned by him November 12, 1850. 
