magnetic phenomena produced by electricity. q 
-some iron ‘filings on a paper, and brought them near the com- 
municating wire, when immediately they were attracted by 
the wire, and adhered to it in considerable quantities, forming 
a mass round it ten or twelve times the thickness of the 
wire : on breaking the communication, they instantly fell off, 
proving that the magnetic effect depended entirely on the 
passage of the electricity through the wire. I tried the same 
experiment on different parts of the wire, which was seven 
or eight feet in length, and about the twentieth of an inch in 
diameter, and I found that the iron filings were every where 
attracted by it ; and making the communication with wires 
between different parts of the battery, I found that iron 
filings were attracted, and the magnetic needle affected in 
every part of the circuit. 
It was easy to imagine that such magnetic effects could 
not be exhibited by the electrified wire without being capable 
of permanent communication to steel. I fastened several steel 
needles, in different directions, by fine silver wire to a wire 
of the same metal, of about the thirtieth of an inch in thick- 
ness and eleven inches long, some parallel, others trans- 
verse, above and below in different directions : and I placed 
them in the electrical circuit of a battery of thirty pairs of 
plates of nine inches by five, and tried their magnetism by 
means of iron filings : they were all magnetic : those which 
were parallel to the wire attracted filings in the same way 
as the wire itself, but those in transverse directions exhibited 
each two poles, which being examined by the test of delicate 
magnets, it was found that all the needles that were placed 
under the wire ( the positive end of the battery being east) 
had their north poles on the south side of the wire, and their 
C 
MDCCCXXI. 
