The New Physics and Its Evolution | Page 3

be discontinuous.
§ 2. Radiations: Wave-lengths and their measurements--Rubens' and
Lenard's researches-- Stationary waves and
colour-photography--Fresnel's hypothesis opposed by

Neumann--Wiener's and Cotton's experiments.
§ 3. The Electromagnetic Ether: Ampère's advocacy of mathematical
expression--Faraday first shows influence of medium in
electricity--Maxwell's proof that light-waves electromagnetic--His
unintelligibility--Required confirmation of theory by Hertz.
§ 4. Electrical Oscillations: Hertz's experiments-- Blondlot proves
electromagnetic disturbance propagated with speed of light--Discovery
of ether waves intermediate between Hertzian and visible
ones--Rubens' and Nichols' experiments--Hertzian and light rays
contrasted--Pressure of light.
§ 5. The X-Rays: Röntgen's discovery--Properties of X-rays--Not
homogeneous--Rutherford and M'Clung's experiments on energy
corresponding to--Barkla's experiments on polarisation of--Their speed
that of light--Are they merely ultra-violet?--Stokes and Wiechert's
theory of independent pulsations generally preferred--J.J. Thomson's
idea of their formation-- Sutherland's and Le Bon's theories--The
N-Rays-- Blondlot's discovery--Experiments cannot be repeated outside
France--Gutton and Mascart's confirmation-- Negative experiments
prove nothing--Supposed wave-length of N-rays.
§ 6. The Ether and Gravitation: Descartes' and Newton's ideas on
gravitation--Its speed and other extraordinary characteristics--Lesage's
hypothesis--Crémieux' experiments with drops of liquids--Hypothesis
of ether insufficient.

CHAPTER VII
WIRELESS TELEGRAPHY
§ 1. Histories of wireless telegraphy already written, and difficulties of
the subject.
§ 2. Two systems: that which uses the material media (earth, air, or

water), and that which employs ether only.
§ 3. Use of earth as return wire by Steinheil --Morse's experiments with
water of canal--Seine used as return wire during siege of
Paris--Johnson and Melhuish's Indian experiments--Preece's telegraph
over Bristol Channel--He welcomes Marconi.
§ 4. Early attempts at transmission of messages through
ether--Experiments of Rathenau and others.
§ 5. Forerunners of ether telegraphy: Clerk Maxwell and
Hertz--Dolbear, Hughes, and Graham Bell.
§ 6. Telegraphy by Hertzian waves first suggested by
Threlfall--Crookes', Tesla's, Lodge's, Rutherford's, and Popoff's
contributions--Marconi first makes it practicable.
§ 7. The receiver in wireless telegraphy--Varley's, Calzecchi--Onesti's,
and Branly's researches-- Explanation of coherer still obscure.
§ 8. Wireless telegraphy enters the commercial stage-- Defect of
Marconi's system--Braun's, Armstrong's, Lee de Forest's, and
Fessenden's systems make use of earth-- Hertz and Marconi entitled to
foremost place among discoverers.

CHAPTER VIII
THE CONDUCTIVITY OF GASES AND THE IONS
§ 1. The Conductivity of Gases: Relations of matter to ether cardinal
problem--Conductivity of gases at first misapprehended--Erman's
forgotten researches--Giese first notices phenomenon--Experiment with
X-rays-- J.J. Thomson's interpretation--Ionized gas not obedient to
Ohm's law--Discharge of charged conductors by ionized gas.
§ 2. The Condensation of water-vapour by Ions: Vapour will not

condense without nucleus--Wilson's experiments on electrical
condensation--Wilson and Thomson's counting experiment--Twenty
million ions per c.cm. of gas--Estimate of charge borne by ion-- Speed
of charges--Zeleny's and Langevin's experiments--Negative ions 1/1000
of size of atoms--Natural unit of electricity or electrons.
§ 3. How Ions are Produced: Various causes of ionization--Moreau's
experiments with alkaline salts--Barus and Bloch on ionization by
phosphorus vapours--Ionization always result of shock.
§ 4. Electrons in Metals: Movement of electrons in metals
foreshadowed by Weber--Giese's, Riecke's, Drude's, and J.J. Thomson's
researches--Path of ions in metals and conduction of heat--Theory of
Lorentz--Hesehus' explanation of electrification by contact--Emission
of electrons by charged body-- Thomson's measurement of positive
ions.

CHAPTER IX
CATHODE RAYS AND RADIOACTIVE BODIES
§ 1. The Cathode Rays: History of discovery--Crookes' theory--Lenard
rays--Perrin's proof of negative charge--Cathode rays give rise to
X-rays--The canal rays--Villard's researches and magneto-cathode
rays-- Ionoplasty--Thomson's measurements of speed of rays-- All
atoms can be dissociated.
§ 2. Radioactive Substances: Uranic rays of Niepce de St Victor and
Becquerel--General radioactivity of matter--Le Bon's and Rutherford's
comparison of uranic with X rays--Pierre and Mme. Curie's discovery
of polonium and radium--Their characteristics--Debierne discovers
actinium.
§ 3. Radiations and Emanations of Radioactive Bodies: Giesel's,
Becquerel's, and Rutherford's Researches--Alpha, beta, and gamma
rays--Sagnac's secondary rays--Crookes' spinthariscope--The

emanation --Ramsay and Soddy's researches upon it--Transformations
of radioactive bodies--Their order.
§ 4. Disaggregation of Matter and Atomic Energy: Actual
transformations of matter in radioactive bodies --Helium or lead final
product--Ultimate disappearance of radium from earth--Energy
liberated by radium: its amount and source--Suggested models of
radioactive atoms--Generalization from radioactive phenomena -Le
Bon's theories--Ballistic hypothesis generally admitted--Does energy
come from without--Sagnac's experiments--Elster and Geitel's contra.

CHAPTER X
THE ETHER AND MATTER
§ 1. The Relations between the Ether and Matter: Attempts to reduce
all matter to forms of ether--Emission and absorption phenomena show
reciprocal action-- Laws of radiation--Radiation of gases--Production
of spectrum--Differences between light and sound variations show
difference of media--Cauchy's, Briot's, Carvallo's and Boussinesq's
researches--Helmholtz's and Poincaré's electromagnetic theories of
dispersion.
§ 2. The Theory of Lorentz:--Mechanics fails to explain relations
between ether and matter--Lorentz predicts action of magnet on
spectrum--Zeeman's experiment --Later researches upon Zeeman
effect-- Multiplicity of electrons--Lorentz's explanation of
thermoelectric phenomena by electrons--Maxwell's and Lorentz's
theories do not agree--Lorentz's probably more correct--Earth's
movement in relation to ether.
§ 3. The Mass of Electrons: Thomson's and Max Abraham's view that
inertia of charged body due to charge--Longitudinal and transversal
mass--Speed of electrons