viil CONTENTS. 



" Lines of force," 68 ; Development of the conception by Lord Kelvin, 

 71 ; Clerk-Maxwell, 76 ; His series of works on the theory of electricity, 

 78; His conception of "tubes of force," 80; " Electrotonic state" of 

 matter, 81 ; Correspondence between velocities of light and electricity, 

 84 ; " Elastic disturbances " of the same medium, 85 ; Consequences on 

 the lines of the theory of Energy, 87 ; Destructive effect of the new 

 theories on the astronomical view, 89 ; Lord Kelvin on the vibrations 

 of the ether, 91 ; Indefiniteness of the electro-magnetic theory, 93. 



CHAPTER VII. 



ON THE PHYSICAL VIEW OF NATURE. 



Recapitulation, 95 ; Insufficiency of the astronomical, atomic, and kinetic 

 views, 96 ; The conception of energy, 96 ; The term first used by Young, 

 98 ; Watt introduces the term " power," 99 ; Poncelet introduces the 

 term " mechanical work," 101 ; Black, Rumford, and Davy, 102 ; Cor- 

 relation of forces, 105 ; Liebig, 105 ; Johannes Miiller, 106 ; F. Mohr, 

 107 ; Mayer, 108 ; Joule, 110 ; Helmholtz, 112 ; "Work" and "energy " 

 introduced by Clausius and Thomson, 115; Sadi Carnot, 117; Carnot 

 introduces the idea of "availability," 119 ; Thomson introduces the idea 

 of "dissipation," 119; Fourier, 120; His influence on Carnot, 122; 

 Clapeyron's graphical method, 123 ; Perpetual motion impossible, 124 ; 

 Application by William and James Thomson, 126 ; The two laws of 

 thermodynamics, 128 ; Summary statement of Thomson (Lord Kelvin), 

 132; Rankine, Zeuner, and Hirn, 133; Revolutions brought about by 

 idea of energy, 137; Helmholtz on "tension," 138; "Potential" and 

 "actual" energy, 139 ; The Scotch school, 141 ; Thomson and Tait, 144 ; 

 Clerk - Maxwell, 145 ; Faraday, 146 ; Helmholtz on electro-dynamics, 

 149; Ostwald's physical chemistry, 153; The factor of "cost" in 

 industry, 155 ; Berthelot and Ostwald, 157 ; Arrhenius, 159 ; Graham 

 and Andrews, 161 ; Dissociation, 163 ; Hittorf and Kohlrausch, 164 ; 

 Victor Meyer on change of chemical views, 165 ; Ostwald's journal, 166 ; 

 Willard Gibbs, 167 ; Entropy, 169 ; Horetmann, 170 ; Helmholtz's "free 

 energy," 173 ; Kelvin's "available energy," 174; Ostwald's 'Allgemeine 

 Chemie,' 176 ; "Kinetics" and "energetics," 180 ; Criticism of mechani- 

 cal view, 183 ; The outcome, 187 ; Recent triumphs of atomic view, 188 ; 

 Modern electrical researches, 189; The term "electron," 193; Diffi- 

 culties of Clerk-Maxwell's theory, 194 ; What are electric charges ? 

 195 ; Dr Larmor's position, 195 ; Objections raised by atomists, 198 ; 

 Artificial character of modern dynamical explanations, 199 ; The phil- 

 osophic problem raised, 199. 



