Recent Developments in Electro-magnetism

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Page 222 - It is quite natural to speak of the coefficient m as the electromagnetic mass of the electron. This mass may be superposed upon the ordinary mass, at least it does not wholly take its place. This leads to an electromagnetic interpretation of mechanics. In this new mechanics, the mass m does not maintain a constant value m* except at very small velocities.
Page 232 - The properties of a ferromagnetic body are then well explained by supposing that the magnetic moments of their atoms are simple multiples of a magneton. Magnetism will then ha.ve a granular structure like electricity.
Page 226 - ... nevertheless consistent in itself. Einstein himself, basing his deductions on this consequence, tried to bring back to the principle of relativity the absolute value which 1 Einstein, Annalen der Physik, vol. 17, p. 902, 1906. 'Einstein, 1. c. and Annalen der Physik, vol. 20, p. 627, 1906; vol. 23, p.
Page 232 - Piccard,* who have reached concordant results close to 0.72 X10-" at 20° C. The theory of the magneton thus has had the merit of fixing definitely this important constant. We are obliged to admit, however, that for ferromagnetic bodies the atom does not possess a unique magnetic moment, but has a certain number of different values according to the temperature and the chemical compound into which it enters.
Page 229 - Rayleigh, Brace, and Troughton before we will be able to build these theories. III. ELECTROMAGNETISM AND RADIATION. The difficulties just described are not the only ones which the modern theory of electromagnetism encounters. Perhaps the gravest ones arise in adapting it to the experimental facts of radiation. We know that thermal radiation in equilibrium in a constant-temperature chamber, and called " black radiation," has a density independent of the particular body producing it.
Page 229 - ... three theoretical laws but also corresponds to the observed distribution of energy in the spectrum of a black body. This formula reduces for large values of \T to the earlier one of Rayleigh, Now, the electromagnetic theory seems to lead almost inevitably to Rayleigh's formula for all wave-lengths in flagrant contradiction to experimental facts. The second formula, indeed, does not give a maximum to the radiation distribution curve and makes the total radiation infinite. This consequence, which...
Page 237 - ... so we will note only a few of the recent results upon which the bulk of the work has been done. (1) With regard to the Hertz effect, the researches from the start showed a great complexity of the phenomenon of photoelectric fatigue — that is, the progressive diminution of the effect observed upon fresh metallic surfaces.
Page 232 - Conference de Bruxelles, 1911. ionizing force, surrounds itself with a cortege of neutral molecules; the residual positive atomic ion does likewise. Thus originate the ordinary positive and negative ions. They are characterized by their mobility K, coefficient of recombination a, and diffusion D. At very low pressures and at high temperatures these assemblages are dissociated little by little to the primitive charged center., We will see that some modification of these ideas will be necessary. (1)...
Page 234 - Blanc a small amount of aqueous vapor diminishes the mobility of the negative ion and increases that of the positive ion in air and in carbonic acid gas (450 and 490 CGS for air instead of 380 and 600). The same occurs with alcohol vapor. The molecules of water and alcohol without doubt remain longer associated with the charged nucleus than those of air, carbonic acid gas, or hydrogen.
Page 236 - initial recombination" discovered by Bragg. According to the latter, the saturation current of a gas ionized by a rays is much more difficult to obtain than when X rays are used. This is due, not to an

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