NEW CONCEPTIONS IN SCIENCE 



into a picture which explains the properties of gases 

 in the bewildering flight and whirl and rebound of 

 their smallest particles, the molecules. The me- 

 chanical theory of heat, that heat is simply the 

 clash of the particles, had been built on the same 

 foundations. A kinetic theory of matter was 

 emerging. In the new view, all is motion ; there is 

 no "rest." Some experiments of M. Berthelot, 

 made with Pean de St. Giles, revealed a new factor 

 in chemical action, the factor of time. This im- 

 plied motion ; it ought to be measurable. 



These two investigators studied the rate of for- 

 mation of some compound ethers in the reaction of 

 alcohol with acids. The experiments threw a new 

 light upon the subject, for they showed that the 

 velocity of the reaction was not merely measurable 

 in time, but conditioned by a variety of physical 

 factors, among others, that of the quantity or mass 

 of the substances present. The formation of the 

 ethers proceeds more and more slowly as the proc- 

 ess goes on, until finally all action comes to an end, 

 even though both alcohol and acid remain in the 

 liquid. This influence of mass, as it is called, has 

 since been disclosed in all chemical processes, and 

 has been developed into a wide theory of chemical 

 equilibrium, which has thrown a new light upon the 

 atomic world. The working out of the theory has 

 fallen to other hands than those of M. Berthelot 



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