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XV. On Statical and Dynamical Ideas in Chemistry. — Part. III. 

 The Atomic Theory. By Edmund J. Mills, D.Sc* 



Contents. 



Introductory Remarks. Primary postulate of the atomic theory. Dalton's 

 views. Atomic motion. The singular relations of formulae and symbols 

 neither suggest nor prove the existence of indivisibles ; the equatorial 

 method leads only to a least common multiple. Instances of the sup- 

 posed explanation of isomerism on atomic principles : chemical structure. 

 Definite proportions may be consistent with infinite divisibility, and are 

 consistent with continuity : illustrations. Absence of evidence that 

 matter and division are mutually related : appeal to philosophy neces- 

 sary. Digby's proof that there are no parts in quantity. The atomic 

 theory shares in the fallacy of materialism, — and of the absolute, so far 

 as that is fallacious. Actual realization of the atom : parallel from 

 phlogiston. Instances of uncertain and contradictory results. Opinions 

 of Newton, Descartes, Leibnitz, Kant, Davy, Wollaston, and Faraday. 

 Nature of the issue. 



A CRITICAL examination of some of the leading ideas rela- 

 ting to Chemical Functions and Chemical Substancef, 

 conducts, by an easy and simple transition, to a discussion of 

 the Atomic Theory. If the reader will admit as sound the cha- 

 racteristic of a universal criterion pointed out in Part I., he may 

 now feel an interest in reading the oldest legend of systematic 

 physics by the light of the latest and best development of modern 

 science. The idea of motion, which is the criterion in question, 

 comes inevitably to be accepted as the sole reliable guide, when 

 a guide is sought in scientific controversy : it does not appeal to 

 nor is it derived from this or that authority ; but, as the common 

 property of every one who reflects, and drives his conclusions to 

 their end, it is immediately and independently available. 



The primary postulate of the atomic theory is the existence of 

 indivisibles. From this demand it has never receded, whatever 

 may have been the state of contemporary science. From Lucre- 

 tius, whose lines 



Hsec neque dissolvi plagis extrinsecus icta 



Possunt ; nee porro penitus penetrata retexi ; 



Nee ratione queunt alia tentata labare. [I. 531-533.] 



[Nor, struck with outer blows, can these dissolve ; 

 Nor, penetrated deep, be disentwined ; 

 Nor, tried in other mode, can waver aught.] 



are explicit upon this point, to the majority of modern chemical 

 writers, this supposition pursues an undeviating course. Upon 

 the different properties of these indivisibles, however, all their 



* Communicated by the Author, 

 t Phil. Mag. S. 4. vol. xl. p. 259. 



