410 PROCEEDINGS OF THE AMERICAN ACADEMY. 



the equation of van der Waals, and modifying this equation only as 

 regards the changeability of a and b. 



4. That it is consistent with the varying specific heats of substances 

 in the solid, liquid, and gaseous states. 



5. That with the help of this theory such physical properties as ten- 

 acity, ductility, malleability, and coefficient of expansion assume for the 

 first time a conceivable consistency. 



6. That upon it may be based a definition of the essential influences 

 of chemical change and equilibrium. 



7. That the variable compressibility of atoms furnishes a plausible 

 explanation for many of the phenomena of quantivalence, including even 

 the feeble affinities holding water of crystallization and other so-called 

 molecular combinations. 



8. That it explains all the tridimensional relations of material, such as 

 stereochemistry and crystal form, at least as well as any other theory. 



9. That with the proviso that electrical energy is a rhythmic mani- 

 festation of energy, — tending to repel itself and therefore to keep upon 

 the surface of material which is susceptible to it, and hence to expand 

 a free atom, — many of the electrical and magnetic phenomena of matter 

 become more conceivable. 



10. That the effect of light in hastening the attainment of chemical 

 equilibrium, and the possibility of storing and emitting light energy 

 possessed by material, may be interpreted in a similar way. 



11. That the careful consideration of all these and other facts leads 

 to a somewhat new conception of the relation between gravitation and 

 chemical affinity, as well as between matter and luminiferous ether. 

 This conception involves simply an antithesis of contracting and expand- 

 ing tendencies, and is thus founded entirely upon an energetic basis. 



12. That the idea is capable of throwing light upon the periodic sys- 

 tem, and the genesis and permanence of the elements. 



13. That it may be applied even to such astrophysical problems as 

 the cause of the sun's heat. 



This is a large program ; some of it is already in manuscript, and more 

 must await further exact experiment. The program is given here only to 

 call attention to the wide possibilities of the consistent introduction of the 

 conception of atomic compressibility into chemistry and molecular physics. 



The present paper is only one step in the direction indicated. It is 

 nevertheless an important step, for it adds approximate quantitative 

 evidence to the previously given qualitative evidence concerning the 

 significance of changing atomic volume. 



