124 Mr. W. H. Walenn's Remarks on the Atomic Theory. 



must ever remain true ; whereas the atomic theory, by which we 

 now explain this great law, may possibly in time give place to 

 one more perfectly suited to the explanation of new facts. - " 



In mathematical science, as, for instance, in the Differential 

 and Integral Calculus, the greatest advantage has been derived 

 from reasoning upon quantities that, in relation to other quan- 

 tities, diminish without limit ; but this diminution, arising as it 

 does from a specific operation or repetition of processes upon a 

 given quantity, never implies annihilation, as Dr. Williamson evi- 

 dently infers when, in order to evolve his results, he is obliged to 

 represent particles to his mind by supposing the operation of divi- 

 sion of a sensible mass into parts (by successive steps) to stop at 

 a certain point yet undetermined. Division of a given mass of 

 matter, say, by successively halving it, will never annihilate it, 

 but will always leave sufficient of it to reason upon, although it 

 may by constant repetition of the process become far too small 

 to be recognizable by the balance ; moreover, however small it 

 may be, it will possess the intrinsic properties of the given mass. 

 Since this view of the subject never supposes the annihilation of 

 matter, it is always competent for the mind to realize the building- 

 up of a mass of matter by the multiplication of the particles to 

 which it has been reduced, possibly for the convenience of theo- 

 retical investigation. When, again, the measure of comparison 

 is weight, it serves no purpose to suppose that matter consists 

 of a collection of individual atoms; for these are not practically 

 weighable, more especially as there is no proof to the eye, the 

 touch, or other sense of the existence of such atoms ; the prac- 

 tical way in this case is evidently to take a definite and arbitrary 

 unit of weight, such as a gramme of hydrogen, for instance, to 

 start with. 



In reference to the second point, if a v « 2 , « 3 , . . . a n represent 

 certain definite weights of the different kinds of matter repre- 

 sented by A,, A 2 , A3, . . . A n , related to each other in the same way 

 as the so-called " atomic " weights of the said different kinds of 

 matter (so that a v instead of being one indivisible unit of hy- 

 drogen, shall mean one gramme of hydrogen, « 2 sixteen grammes 

 of oxygen, &c), the proportions of these definite weights in rela- 

 tion to each other and in relation to the law of multiple proportions 

 will be the same as if any other definite weights (however small) 

 were taken. It follows that the existence of physical atoms is 

 not only not a necessary consequence of the facts that have been 

 observed respecting the combining proportions of various sub- 

 stances, or the multiple proportions of pairs of substances, but is 

 quite immaterial to the question at issue. The assumption of a unit 

 independent of the laws of nature is not new in science, but is a 

 necessary means of orderly arrangement and of establishing re- 



