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. CHAPTER XXIV. THERMOELECTRICITY 175 Exp. 174, To find whether electricity can be produced by heat.--Home-made Thermopile.--Thermoelectricity.--Peltier Effect.--Thermopiles. CHAPTER XXV. INDUCED CURRENTS 178 Electromagnetic Induction.--Exp. 175, To find whether a current can be generated with a bar magnet and a hollow coil of wire.--Discussion.--Induced Currents and Work.--Exp. 176, To find whether a current can be generated with a bar magnet and a coil of wire having an iron core.--Exp. 177, To find whether a current can be generated with a horseshoe magnet and a coil of wire having an iron core.--Induced Currents and Lines of Force.--Exp. 178, To find whether a current can be generated with an electromagnet and a hollow coil of wire.--Exp. 179, To find whether a current can be generated with an electromagnet and a coil of wire having an iron core.--Discussion of Exps. 178-179.--Exp. 180, To study the effect of starting or stopping a current near a coil of wire or other closed circuit.--Exp. 181, To study the effect of starting or stopping a current in a coil placed inside of another coil.--Discussion of Exps. 180-181.--Direction of Induced Current.--Laws of Induction.--Primary and Secondary Currents.--Exp. 182, To see what is meant by alternating currents.--Direct and Alternating Currents.--Self-induction; Extra Currents. CHAPTER XXVI. THE PRODUCTION OF MOTION BY CURRENTS 187 Currents and Motion.--Exp. 183, Motion produced with a hollow coil and a piece of iron.--Exp. 184, Motion with hollow coil and bar magnet.--Exp. 185, Motion with electromagnet and piece of iron.--Exp. 186, Motion with electromagnet and bar magnet.--Exp. 187, Motion with electromagnet and horseshoe magnet.--Exp. 188, Motion with two electromagnets.--Discussion of Exps. 183-188.--Exp. 189, Rotary motion with a hollow coil of wire and a permanent magnet.--Exp. 190, Rotary motion with an electromagnet and a permanent magnet.--Discussion of Exps. 189-190. CHAPTER XXVII. APPLICATIONS OF ELECTRICITY 192