475. ¨ Orsted’s discovery of the action of an electric current on a magnet
476. The space near an electric current is a magnetic field
477. Action of a vertical current on a magnet
478. Proof that the force due to a straight current of indefinitely great length varies inversely as the distance
479. Electromagnetic measure of the current
480. Potential function due to a straight current. It is a function of many values
481. The action of this current compared with that of a magnetic shell having an infinite straight edge and extending on one side of this edge to infinity
482. A small circuit acts at a great distance like a magnet
483. Deduction from this of the action of a closed circuit of any form and size on any point not in the current itself
484. Comparison between the circuit and a magnetic shell
485. Magnetic potential of a closed circuit
486. Conditions of continuous rotation of a magnet about a current
487. Form of the magnetic equipotential surfaces due to a closed circuit. Fig. XVIII
488. Mutual action between any system of magnets and a closed current
489. Reaction on the circuit
490. Force acting on a wire carrying a current and placed in the magnetic field
491. Theory of electromagnetic rotations
492. Action of one electric circuit on the whole or any portion of another
493. Our method of investigation is that of Faraday.
494. Illustration of the method applied to parallel currents
495. Dimensions of the unit of current
496. The wire is urged from the side on which its magnetic action strengthens the magnetic force and towards the side on which it opposes it.
497. Action of an infinite straight current on any current in its plane
498. Statement of the laws of electromagnetic force. Magnetic force due to a current
499. Generality of these laws
500. Force acting on a circuit placed in the magnetic field
501. Electromagnetic force is a mechanical force acting on the conductor, not on the electric current itself