Sec. 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

Sec. 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.

Sec. 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.

Sec. 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.

Sec. 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

Sec. 1.  Solution:  Kirchhoff’s, Gibb’s, Duhem’s and Van t’Hoff’s researches.

Sec. 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.

Sec. 3.  Osmosis applied to Solution:  Van t’Hoff’s discoveries—­Analogy between dissolved body and perfect gas—­Faults in analogy.

Sec. 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.