Electromagnets.--Cores of Electromagnets.--Exps. 158-163,
To study straight electromagnets; Lifting power; Residual
magnetism of core; Magnetic tick; Magnetic figures; Magnetic
field.--Horseshoe Electromagnets.--Use of Yoke.--Experimental
Magnets.--Method of Joining Coils.--Exps. 164-173, To study
horseshoe electromagnets; To test the poles; To study the
inductive action of one core upon the other; Magnetic figures;
Permanent Magnetic Figures; Lifting power; Residual magnetism
when magnetic circuit is closed.--Closed Magnetic Circuits.