44 On the magnetic Phwenomena 
I found, in repeating the experiments of M. Qérsted with a 
Voltaic apparatus of one hundred pair of plates of four inches, 
that the south pole of a common magnetic needle (suspended in 
the usual way) placed under the communicating wire of plati- 
num, (the positive end of the apparatus. being on the right hand,) 
was strongly attracted by the wire, and remained in contact with 
it, so as entirely to alter the direction of the needle, and to over- 
come the magnetism of the earth. This I could only explain by 
supposing that the wire itself became magnetic during the pas- 
sage of the electricity through it, and direct experiments, which 
1 immediately made, proyed that this was the case. I threw 
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 break- 
ing the communication, they instantly fell off, proving that the 
magnetic effect depended: entirely on the passage of the electri- 
city 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 perma- 
nent 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 thickness and eleven 
inches long, some parallel, others transverse, above and below, 
in different directions: and | 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 direc- 
tions 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 
south poles on the north side; and that those placed over, had 
their south poles turned to the south, and their north poles turned 
to the north; and this was the case whatever was the inclination 
of the needles to the horizon. On breaking the connexion, all 
the steel needles that were on the wire in a transverse direction 
retained their magnetism, which was as powerful as ever, whilst 
those which were parallel to the silver wire appeared to lose it 
at the same time as the wire itself, ch ng 5 ee at= 
