The New Physics and Its Evolution | Page 2

in Physical Theory-- Revival of metaphysical speculation and influence of Descartes: all phenomena reduced to matter and movement-- Modern physicists challenge this: physical, unlike mechanical, phenomena seldom reversible--Two schools, one considering experimental laws imperative, the other merely studying relations of magnitudes: both teach something of truth--Third or eclectic school-- Is mechanics a branch of electrical science?

CHAPTER II
MEASUREMENTS
§ 1. Metrology: Lord Kelvin's view of its necessity-- Its definition
§ 2. The Measure of Length: Necessity for unit-- Absolute length--History of Standard--Description of Standard Metre--Unit of wave-lengths preferable--The International Metre
§ 3. The Measure of Mass: Distinction between mass and weight--Objections to legal kilogramme and its precision--Possible improvement
§ 4. The Measure of Time: Unit of time the second--Alternative units proposed--Improvements in chronometry and invar
§ 5. The Measure of Temperature: Fundamental and derived units--Ordinary unit of temperature purely arbitrary--Absolute unit mass of H at pressure of 1 m. of Hg at 0° C.--Divergence of thermometric and thermodynamic scales--Helium thermometer for low, thermo-electric couple for high, temperatures--Lummer and Pringsheim's improvements in thermometry.
§ 6. Derived Units and Measure of Energy: Importance of erg as unit--Calorimeter usual means of determination--Photometric units.
§ 7. Measure of Physical Constants: Constant of gravitation--Discoveries of Cavendish, Vernon Boys, E?tv?s, Richarz and Krigar-Menzel--Michelson's improvements on Fizeau and Foucault's experiments-- Measure of speed of light.

CHAPTER III
PRINCIPLES
§ 1. The Principles of Physics: The Principles of Mechanics affected by recent discoveries--Is mass indestructible?--Landolt and Heydweiller's experiments --Lavoisier's law only approximately true--Curie's principle of symmetry.
§ 2. The Principle of the Conservation of Energy: Its evolution: Bernoulli, Lavoisier and Laplace, Young, Rumford, Davy, Sadi Carnot, and Robert Mayer--Mayer's drawbacks--Error of those who would make mechanics part of energetics--Verdet's predictions--Rankine inventor of energetics--Usefulness of Work as standard form of energy--Physicists who think matter form of energy-- Objections to this--Philosophical value of conservation doctrine.
§ 3. The Principle of Carnot and Clausius: Originality of Carnot's principle that fall of temperature necessary for production of work by heat-- Clausius' postulate that heat cannot pass from cold to hot body without accessory phenomena--Entropy result of this--Definition of entropy--Entropy tends to increase incessantly--A magnitude which measures evolution of system--Clausius' and Kelvin's deduction that heat end of all energy in Universe--Objection to this-- Carnot's principle not necessarily referable to mechanics --Brownian movements--Lippmann's objection to kinetic hypothesis.
§ 4. Thermodynamics: Historical work of Massieu, Willard Gibbs, Helmholtz, and Duhem--Willard Gibbs founder of thermodynamic statics, Van t'Hoff its reviver--The Phase Law--Raveau explains it without thermodynamics.
§ 5. Atomism: Connection of subject with preceding Hannequin's essay on the atomic hypothesis--Molecular physics in disfavour--Surface-tension, etc., vanishes when molecule reached--Size of molecule--Kinetic theory of gases--Willard Gibbs and Boltzmann introduce into it law of probabilities--Mean free path of gaseous molecules--Application to optics--Final division of matter.

CHAPTER IV
THE VARIOUS STATES OF MATTER
§ 1. The Statics of Fluids: Researches of Andrews, Cailletet, and others on liquid and gaseous states-- Amagat's experiments--Van der Waals' equation--Discovery of corresponding states--Amagat's superposed diagrams--Exceptions to law--Statics of mixed fluids-- Kamerlingh Onnes' researches--Critical Constants-- Characteristic equation of fluid not yet ascertainable.
§ 2. The Liquefaction of Gases and Low Temperatures: Linde's, Siemens', and Claude's methods of liquefying gases--Apparatus of Claude described--Dewar's experiments--Modification of electrical properties of matter by extreme cold: of magnetic and chemical-- Vitality of bacteria unaltered--Ramsay's discovery of rare gases of atmosphere--Their distribution in nature--Liquid hydrogen--Helium.
§ 3. Solids and Liquids: Continuity of Solid and Liquid States--Viscosity common to both--Also Rigidity-- Spring's analogies of solids and liquids--Crystallization --Lehmann's liquid crystals--Their existence doubted --Tamman's view of discontinuity between crystalline and liquid states.
§ 4. The Deformation of Solids: Elasticity-- Hoocke's, Bach's, and Bouasse's researches--Voigt on the elasticity of crystals--Elastic and permanent deformations--Brillouin's states of unstable equilibria--Duhem and the thermodynamic postulates-- Experimental confirmation--Guillaume's researches on nickel steel--Alloys.

CHAPTER V
SOLUTIONS AND ELECTROLYTIC DISSOCIATION
§ 1. Solution: Kirchhoff's, Gibb's, Duhem's and Van t'Hoff's researches.
§ 2. Osmosis: History of phenomenon--Traube and biologists establish existence of semi-permeable walls--Villard's experiments with gases--Pfeffer shows osmotic pressure proportional to concentration-- Disagreement as to cause of phenomenon.
§ 3. Osmosis applied to Solution: Van t'Hoff's discoveries--Analogy between dissolved body and perfect gas--Faults in analogy.
§ 4. Electrolytic Dissociation: Van t'Hoff's and Arrhenius' researches--Ionic hypothesis of--Fierce opposition to at first--Arrhenius' ideas now triumphant --Advantages of Arrhenius' hypothesis--"The ions which react"--Ostwald's conclusions from this--Nernst's theory of Electrolysis--Electrolysis of gases makes electronic theory probable--Faraday's two laws--Valency-- Helmholtz's consequences from Faraday's laws.

CHAPTER VI
THE ETHER
§ 1. The Luminiferous Ether: First idea of Ether due to Descartes--Ether must be imponderable--Fresnel shows light vibrations to be transverse--Transverse vibrations cannot exist in fluid--Ether must 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