On Physical Lines of Force/Figures

On Physical Lines of Force → Figures

Nineteen drawings prepared for this edition. Those marked after Maxwell follow the composition of his Plate V; the rest are explanatory and have no counterpart in the printed paper.

Part I — magnetic phenomena

Fig. A — Lines of force about a bar magnet

Fig. A. Lines of force about a bar magnet. The iron-filings experiment, and Maxwell's definition of a line of force. → The introductory discussion

Fig. B — The centrifugal force of one vortex

Fig. B. The centrifugal force of one vortex. Pressure at the axis, at the circumference, and the mean parallel to the axis. → Prop. I

Fig. C — The two components of the stress

Fig. C. Tension along the lines, pressure across them. Why unlike poles attract and like poles repel on one state of stress. → Why spinning makes a pull

Fig. K — Parallel vortices make an anisotropic medium

Fig. K. A bundle of parallel vortices. The medium spreads sideways and shortens along the axes. → Prop. I

Fig. S — Resolving the stress on an element of the medium

Fig. S. The stress on a cube of the medium. Hydrostatic pressure plus a tension along the vortex axis, projected on the coordinate planes. → Prop. II · modern form

Part II — electric currents

Fig. D — Vortex cells and the particles between them

Fig. D. Vortex cells and the particles between them. After Maxwell, Plate V. fig. 2. The current AB, the rows of cells turning oppositely above and below it, and the idle-wheel particles at every cell corner. → The mechanism

Fig. E — The electric circuit, the line of force, and the vortices

Fig. E. Circuit, line of force, and vortices. After Maxwell, Plate V. fig. 1. Fixes the handedness relating current direction to the sense of rotation. → The mechanism

Fig. F — The anchor ring

Fig. F. The anchor ring. After Maxwell, Plate V. fig. 3. Induction with no external magnetic field anywhere. → Induced currents · the vector potential

Fig. G — Why a layer of particles is needed

Fig. G. The idle wheel. Two vortices in direct contact cannot both turn the same way; a particle between them can make them. → Prop. IV

Fig. L — How an induced current arises

Fig. L. How an induced current arises. Three stages: the current starts, the neighbouring vortices resist being spun up, and the next layer of particles is driven backwards. → Induced currents

Part III — statical electricity

Fig. M — Conductor and dielectric compared

Fig. M. The porous membrane and the elastic one. Conduction and induction as two independent qualities of bodies. → Conduction and induction

Fig. H — The cell yields, and pushes back

Fig. H. The cell yields, and pushes back. Electromotive force distorts a cell; the elastic reaction balances it; the particles come to rest displaced. → Prop. XIII

Fig. I — The variation of displacement is itself a current

Fig. I. The displacement current closes the circuit. The charging capacitor, and the two surfaces spanning one loop. → Prop. XIV

Fig. J — Transverse undulations of the electromagnetic medium

Fig. J. A transverse undulation. Displacement and magnetic force at right angles to each other and to the direction of travel. → Prop. XVI · the wave equation

Fig. R — The coincidence that settled it

Fig. R. The two measures of electricity. Their ratio is a velocity; Weber and Kohlrausch measured it; Fizeau had measured the speed of light. → The unit ratio

Part IV — polarized light

Fig. N — Why magnetism turns the plane of polarization

Fig. N. Magnetic rotation of the plane of polarization. The two circular components travel at different speeds in a medium whose vortices are already turning. → Why magnetism must be rotatory

Reference figures

Fig. O — From work round a circuit to the curl

Fig. O. Circulation and the curl. Maxwell's verbal statement of the current law, and what it becomes when the loop shrinks to a point. → Ampère–Maxwell

Fig. Q — A concordance of notation

Fig. Q. A concordance of notation. Maxwell's 1861 symbols and their modern equivalents. → Notation

Fig. P — Where the paper sits

Fig. P. Chronology, 1820 to 1873. → Chronology

A note on the figures

These are original drawings, not reproductions of the 1862 plate. No page image of Maxwell's Plate V was available for this edition, so the three marked after Maxwell were reconstructed from his textual descriptions of them — which are detailed enough to fix the composition but not the draughtsmanship. His fig. 2 in particular is drawn here as a regular hexagonal tiling with a particle at every vertex; the printed figure may differ in the number of rows and in the exact packing. See Sources and editorial method.

All figures are SVG and will scale without loss. If they do not display, they were probably not uploaded — an XML import carries page text only. See On Physical Lines of Force/Rendering test.

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