850 



LORD KELVIN. 



actual magnitudes concerned (the number of molécules per cubic centi- 

 mètre of a gas, the mass in grammes of an atom of any substance, the 

 diameters of the atoms, the absolute value of the electric quantity in an 

 electrion, the effective mass or inertia of an electrion) seem to show 

 that the intermolecular electric forces are more than amply great enough 

 to account for heat of chemical combination, and every mechanical 

 action manifested in chemical interactions of ail kinds. We might be 

 tempted to assume that ail chemical action is electric, and that ail 

 varieties of chemical substance are to be explained by the numbers of 

 the electrions required to neutralize an atom or a set of atoms (§ 6 

 above) ; but we can feel no satisfaction in this idea when we consider 

 the great and wild variety of quality and affmities manifested by the 

 différent substances or the différent „cheinical éléments"; and as we are 

 assuming the electrions to be ail alike, we must fall back on Pather 

 Boscovioh, and require him to explain the différence of quality of diffé- 

 rent chemical substances, by différent laws of force between the différent 

 atoms. 



§ 27. Consider lastly a solid; that is to say, an assemblage in which 

 the atoms have no relative motions, except through ranges small in 

 comparison with the shortest distances between their centres. *) The first 

 thing that we remark is that every solid would, at zéro of absolute tem- 

 pérature, (that is to say ail its atoms and electrions at rest) be a perfect 

 insulator of electricity under the influence of electric forces, moderate 

 enough not to piuck electrions out of the atoms in which they rest 

 stably when there is no disturbing force. The limiting value of F here 

 inclicated for perfect insulation, I shall for brevity call the disruptional 

 force or disruptional intensity. It is clear that this disruptional force is 

 smaller the greater the number of electrions within an atom. 



§ 28. The electro-inductive permeability of a solid at zéro tempéra- 

 ture is calculable by the static dynamics of § 24, modified by taking 

 into account forces on the electrions of one atom due to the attractions 

 of neighbouring atoms and the repulsions of their electrions. Without 



x ) I need scarcely say that it is only for simplicity in the text that we con- 

 veniently ignore Roberts-Austen's admirable discovery of the interdiffusion of 

 solid gold and solid lead, found after a pièce of one métal is allowed to rest 

 on a pièce of the other for several weeks, months, or yeais. 



