162 On the Atomic Theory. 



had no conception of the laws that regulated the limitation, be- 

 cause they were not aware that bodies united particle to particle 

 and atom to atom in certain but limited proportions. In short, 

 the cause of this law was unknowai until I published my Com" 

 parative View, 



The writer tells us that the true nature of metallic oxides 

 was not known until Lavoisier's time : — How could it be known, 

 when their oxidation was solely attributed to a loss of their phlo- 

 giston? But the first idea of metals uniting to different doses of 

 oxygen, like sulphur, charcoal and azote, will be found in my 

 Comparative View. 



'' Although chemists have frequently used a language which 

 appeared to show their acquaintance with the real cause of the 

 definite proportions ; such as one compound being formed by one 

 proportion, dose or particle, of one of its elements ; and another 

 with two proportions, doses or particles * : on the other hand, 

 we find expressions which would favour the idea of indefinite 

 proportions ; such as bodies losing a small portion of their oxy- 

 gen, or absorbing a little oxygen from the atmosphere." The 

 drift of the latter part of this passage will appear presently. 



** The most decided language used in any chemical work be- 

 fore the discoveries of Mr. John Dalton f, giving any idea that 

 the doses are limited by distinct atoms, will be found in a work 

 by Mr. Higgins, entitled ' A Comparative View of the Phlogistic 

 and Antiphlogistic Theories.' This work was written for the ex- 

 press purpose of combating the phlogistic theory, and princi- 

 pally in answer to Kirwan's Treatise of Phlogiston. 



" In order to show the contradictions and absurdities of the 

 phlogistic doctrine, which under the nanre of phlogiston con- 

 founded a number of bodies which were very different, he ex- 

 hibited by diagrams a number of chemical operations, in which 

 he supposed the elementary bodies concerned to be ultimate 

 particles, and their immediate compounds molecules. He in 

 the same diagrams also used immbers, which he supposed to 

 be estimates of the strength of affinity of the combining particles. 

 By this means he very successfully showed many of the incon- 

 sistencies which must be admitted to explain the phsenomena 

 on the phlogistic theory. In this mode of proceeding, however, 

 the numbers expressing the relative attractions served his pur- 

 pose much more than the consideration of the proportions being 

 caused by distinct atoms ; and the language which would induce 

 the belief that he had such a conception of the nature of ele- 

 mentary matter occurs only in a very few parts of his work." 



* No such language was used until I had written, 

 ■f It would puzzle the first philosophers of Europe to discover any thing 

 newinMr.Dalton's work, except his errors which I have repeatedly pointed 



out, The 



