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from iron as I believe it possible to obtain them, I think 
the phenomena of the variable magnetic and dia-magnetic 
states of metals may be safely considered as being inde- 
pendent of the presence of iron or other constantly magnetic 
bodies. 
In experimenting upon the metals — gold, silver, copper, 
lead, and zinc, my attention was particularly drawn to the 
phenomena described by Dr. Faraday, and by him called 
‘‘ revulsion,” and I found that the form of small flat discs 
was a particularly convenient one for exhibiting these. Dr. 
Faraday noticed the phenomena of revulsion, particularly 
in copper; I, however, found that it is exhibited in nearly 
all metals which are less magnetic than platinum, or less 
dia-magnetic than antimony. I noticed that the direction 
of the revulsive motion is different in magnetic and in 
dia-magnetic metals. I adopt Dr. Faraday’s term revul- 
sion, and I call the revulsion repulsive when the disc 
subjected to experiment is repelled on breaking circuit; 
and attractive when the disc is attracted under the like 
circumstances. I also noticed that in the metals, whether 
pure or compound, which passed from the magnetic to the 
dia-magnetic state, the direction of the revulsion also 
changed. That such a body, exhibiting attraction as 
magnetic, was vigorously attracted through a small space 
on making battery contact ; and as vigorously repelled 
on breaking the circuit. That when the same body, by 
increasing the battery power, or more conveniently by 
approximating the polar pieces, was made to pass into 
the dia-magnetic state, the directions of such revulsive 
motions changed — that on making contact the metal was 
repelled; and that on breaking contact it was attracted; 
I found motions were in some cases to be relied on, 
as pointing out the magnetic and dia-magnetic state of 
the metal, when the steady pointing of the piece axially 
