1) Take a plank and make a hole as shown in figure.
2) Place this plank on the table.
3) Now place a retard stand on the plank.
4) Pass 24 gange of copper wire through hole of the plank and rubber knob of the
retort stand in such a way that the wire should be arranged in vertical position
and it should not tough other material of the stand.
5) Connect the two ends of the wire to a battery via switch.
6) Place 6 to 10 magnetic compasses in circular path as its centre coinsides the hole.
7) Use 3 - volt battery in circuit. Switch on current flows through wire.
8) You may notice that they are directed as tangents to the circle.
9) Magnetic lines, are closed. This can be verified by sprinkling iron filings around the wire when current exists in the circuit.