174 Remarks on the Essay of Dr, Berzelius [March, 



Article III. 



Remarks on the Essay of Dr. Berzelms on the Cause of Chemical 

 Proportions. By John Dalton. 



(Read before the Manchester Society, Dec. 24, 1813.) 



It may perhaps seem premature to animadvert on an essay before 

 the whole of it has been published ; but as Dr. Berzelius has stated 

 certain objections to the atomic theory of chemistry in that pait of 

 his essay published iu the Annals oj Philosophy for this month, 

 which, if left unanswered, way be thought by some to present 

 insuperable dittlculiies, I have judged it expedient to make a few 

 remarks on the subject immediately, by way of obviation. Engaged 

 as I have been for some years past, and still continue to be, in a 

 labyrinth of chemical investigation, it may well be imagined I 

 cannot find much time for controversy ; yet the scruples of one 

 who has so eminently distinguislied himself as a fellow labourer in 

 the same field of science, and whose views and opinions in a great 

 measure approximate to my own, are certainly entitled to considera- 

 tion. Whatever our theoretical speculations may be, they are of little 

 avail unless supported by facts ; and, notwithstanding the modern im- 

 provements in the practice of chemistry, no theory of it can advance 

 far without meeting with the difficulties which too often arise from 

 inaccurate observation. I hope to prove to the satisfaction of Dr. 

 Berzelius that some of the difficulties he finds in pursuing the 

 atomic theory are of this kind, and that the rest are only imaginary. 



The first division of Dr. Berzelius' essay, on the relation between 

 Berthollet's theory of affinities and the laws of chemical proportion, 

 contains an admirable exposition of those facts which Berthollet 

 brought forward in so conspicuous a point of view in his chemical 

 theory, and which his zealous followers have magnified in a still 

 greater degree. A better explanation could, I think, be scarcely 

 given in fewer words. 



In the second division on the cause of chemical proportions, Dr, 

 Berzelius, after ascribing to me the principal share in announcing 

 and developing the corpuscular or atomic theory, proceeds to give 

 an explanation of what he conceives it to be. His, ideas on this 

 head are somewhat at variance with mine ; and this is one point 

 on which I wish to be clearly understood, and shall endeavour in 

 what follows to enable the reader to discriminate betwixt us. 



Dr. B. seems to hold it necessary that all atoms should be of the 

 same size. This, he thinks, is required in order to form bodies into 

 regular figures. Now this is no part of my doctrine. I do maintain 

 that all the atoms of any homogeneous body. A, are of the same 

 size as well as weight; and that all the atoms of B are of the same 

 size and weight ; but I see no sufficient reason for concluding that 

 the atoms of A are of the same size as those of B. The probability 



