1814.] Wiggins on the Atomic Theory, &c. 55 



as the number of atoms held in combination by any atom, a. 

 3. That the weight of atoms may be determined from chemical 

 analysis. 



Now as to the first point, namely, that bodies consist of atoms, 

 and that chemical combination consists in the union of one atom of 

 one body with one atom of another body, or of a certain determi- 

 nate number of the atoms of one body with a determinate number of 

 the atoms of another ; I am surprised that such a proposition should 

 be claimed by any living chemist as a discovery. It was the doctrine 

 of Sir Isaac Newton, as is obvious from the thirty-first query at the 

 end of his Optics ; and I conceive it has been the uniform doctrine 

 of all British chemists since his time. I do not know what was the 

 case at Oxford, where Mr. Higgins appears to have studied ; but at 

 Edinburgh it was universally considered as a first principle. I was 

 informed by Professor Robinson that it had been taught by Dr. 

 Cullen ; and Dr. Pearson has assured me, from his own personal 

 knowledge, that the atomic doctrine constituted the basis of Dr. 

 Cullen's chemistry. Dr. Fordyce must have been a lecturer on 

 chemistry in London while Mr. Higgins was actively engaged in 

 the study of chemistry. Now Dr. Pearson informs me that he not 

 only taught the atomic doctrine, but was of opinion that bodies are 

 only capable of uniting particle to particle, or one particle of one 

 bodv with one particle of another. This was one of my own early 

 opinions, which I adopted when a student, and gave up, after the 

 Daltonian theory induced me to examine the subject with more 

 precision than 1 had previously done. This being the matter of 

 fact, and these the views which 1 entertained when I read Mr. 

 Higgins' book, he will not be surprised when I inform him that I 

 found nothing new in it as far as this point, which he seems to 

 claim as a discovery exclusively his own, is concerned. If after 

 reading this statement he is not satisfied that the atomic doctrine 

 was known before the publication of his book, I would advise him 

 to peruse the article Affinity in the Encyclopedie Methodique, 

 which was written several years before his Comparative View. Let 

 him read likewise the first section of Bergman's treatise on Elective 

 Attract ion, which was translated into English by his friend Dr. 

 Beddoes. 



As to the second point which Mr. Higgins claims as a discovery 

 of his own, that the strength of affinity is inversely as the number 

 of atoms united, I have it not at present in my power to consult 

 those works, in which I think 1 recollect that the doctrine is taught, 

 and which were published before his Comparative View. I believe 

 it is explicitly taught somewhere in the first volume of the chemical 

 part of the Encyclopedie Methodique, which is of prior date to 

 that publication ; but whether under the head of Ajjinitc, or not, 

 I am not sure, as 1 have not had the work in my possession for 

 many years. It was h doctrine which was familiar to me before I 

 BW Air. Higgins' work, a doctrine which 1 had imbibed with the 

 first rudiments of my chemical knowledge. He will not be sur- 



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