INDEX OF SUBJECTS. 649 



Ellipsoid. Cylinder 370 



Barlow's Problem 370 



Anisotropic Bodies 375 



Experimental Determination of the Coefficients of Magnetisation . . . 376 



Displacement of Bodies in a Magnetic Field. Attractions and Repulsions . 377 



Equilibrium of Long Bodies in a Uniform Field 380 



Equilibrium of Bodies in a Variable Field 381 



Oscillations of an Infinitely Small Isotropic Needle 383 



Influence of Temperature , . 384 



CHAPTER V. ON MAGNETS. 



Magnetisation 385 



Induction of a Magnet on Itself. Demagnetising Force 385 



Particular Cases of Magnetisation. Sphere 387 



Ellipsoid 388 



Anchor Ring. Tore 388 



Cylinder 388 



Any Given Magnets. Experimental Methods 388 



Oscillations 389 



Torsion Balance 389 



Use of Soft Iron 389 



Measurement of the Flow by Induction Currents 390 



Distribution of the Fictive Layer 391 



Cylindrical Magnets 392 



Empirical Formulae 393 



Hypothesis on the Constitution of Magnets 398 



Weber's Theory 399 



Maxwell's Theory 403 



Jamin's Observations 405 



Influence of Temperature 406 



CHAPTER VI. MAGNETIC CONDITION OF THE 

 GLOBE. 



Gauss' Method 407 



Magnetic Parallels 407 



Magnetic Equator 408 



Terrestrial Magnetic Poles 409 



False Pole. Properties of a Closed Polygon 410 



Introduction of Geographical Co-ordinates 413 



Expression of Potential . 415 



Is the Magnetism of the Earth in the Interior only? 416 



Influence of the Sun and Moon 417 



