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.

Sec. 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.

Sec. 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.

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 Rigid