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sion, as dia-magnetics ; and I found that after this change 
of condition the phenomena of revulsion were exhibited 
as before, but in a reverse direction ; and that when the 
magnetic force was sufficiently energetic, repulsion took 
place on making contact, followed by attraction on breaking 
contact. In experimenting upon lead and zinc, if the 
support be moved to one side, so that one side of the disc 
just touch the flat end of the polar piece, the disc is 
repelled on making contact, and is held at a small distance 
from the polar piece, whilst the current is continued ; but 
on breaking contact it is briskly attracted by the polar 
piece. To produce the last mentioned effects in a decided 
manner, although the effect may be observed with one polar 
piece, yet it is advisable to have the two close together, 
as the magnetic force does not appear to be sufficiently 
concentrated in the one piece if the other be not approxi- 
mated to it. 
It might be supposed that as gold, silver, copper, lead, 
tin, zinc, and cadmium, take an axial position when the 
polar pieces are distant, and an equatorial one when they 
are close, that neutral points would be found at which 
neither attraction nor repulsion would take place. I found 
that this happened with lead; but with gold, and particu- 
larly with zinc, the disc was attracted when contact was 
made, but afterwards, during a few seconds, it slowly moved 
to the equatorial position; moving extremely sluggishly, in 
the manner particularly noticed by Dr. Faraday with regard 
to copper. But, although during this sluggish state, the 
disc appeared to be little affected by any directive force 
towards the axial or equatorial position, yet, on breaking 
battery contact, the revulsive force was most strongly de- 
veloped. And it was very remarkable that if the contact 
were broken before the disc had assumed an equatorial 
position, the revulsion was from the nearest polar piece, 
