EXPERIMENT 26. To study the inductive action of a magnet upon a piece of soft iron.
Apparatus. Horseshoe magnet, H M; iron filings, I F; a piece of soft iron wire about an inch long, I W ([Fig. 12]), placed upon the N pole of H M; compass, O C (No. 18), ([§ 32]).
55 Directions. (A) Test the lower end of I W for magnetism with I F.
(B) Leaving I W upon the N pole of H M, test the pole at the lower end of I W with O C, to determine whether it is N or S.
(C) Jar I W ([Exp. 19]), then place it upon the S pole of H M, and again test the polarity of the lower end.
56. Polarization; Pole Pieces. The wire, I W ([Fig. 12]), was acted upon by induction ([Exp. 24]) and behaved like a magnet. Poles were produced in it, so we say that the wire was polarized. Pieces of iron, placed upon the poles of a magnet, are called pole pieces. It should be noted that the lower end of the wire has a pole like the pole of H M, to which it is attached.
EXPERIMENTS 27–30. To study pole pieces.
Apparatus for Experiments 27–30. Horseshoe magnet, H M; soft iron wires; iron filings, I F.
57. Directions. (A) Suspend two wires, each about an inch long ([Fig. 13]) from one pole of H M. Do their lower ends attract or repel each other?
