166 On the Atomic Theory. 



knew as well as Richter, that in the gross, one quantity of alkali 

 required a certain quantity of acid to saturate each other, — and 

 what more can he attribute to Richter? It has nothing to do 

 witli the atomic theory and definite proportions of particles or 

 atoms. 



And as to what relates to metallic precipitations, he is wrong 

 i;i many respects, as I have shown in my Comparative View, 

 page 263, which the following extract will show: "Should the 

 precipitant he unal)le to take up the whole of the oxygen of the 

 precipitated metal, it falls down in the state of a semioxide. 

 Thus lead and silver will precipitate gold from its solution of a 

 dull purple colour, while copper and iron throw it down in its 

 nu'tailic state." 



I now come to the most singular passage of all, as it exhibits 

 tlie most glaring prejudice and ignorance that could flow from 

 the mind of any man that could have any pretensions to science; 

 it is as follows : " It is the means of drawing these inferences 

 arising from the mutual fitness of those parts of bodies which 

 combine, tliat con^^titutes the importance of the Atomic Theory; 

 and it is for the establishment of this new principle that we are 

 indebted to Mr. John Dalton. When Mr. Higghis can show 

 from the data given in his work, that similar inferences could be 

 drawn, he then will be entitled to share in the merit of the dis- 

 covery of the Atomic Theory. We say share with him ; for we 

 are firmly convinced that Mr. Dalton had never read Mr. Hig- 

 gins's book previous to the publication of his own work," 



There is nothing new, as I said before, in these facts, tliey were 

 known before 1 wrote my Comparative View; and the mutual fit- 

 ness (which by the by is an odd expression) of some of them, for 

 it does not extend to all saline bodies, was familiar to every ex- 

 perimental chemist, and Mr. Dalton has nothing to do with it; 

 nor does it immediately relate to the Atomic Theory. 

 " When Higgins can show that similar inferences, &c." 

 I will addyce some facts which, according to the writer, will 

 " entitle me to share in the Atomic Theory." In the section on 

 the precipitation of metals by each other, page 260 Comparative 

 View, will be found a diagram representing the principles on 

 wiiich one metal precipitates another. The precipitation of 

 copper in its metallic state from its solution in sulphuric acid by 

 iron, was adduced as an example. The diagram represents by 

 U!eans of numbers the relative forces of attraction of the different 

 elements in a molecule of sulphate of copper, and also the in- 

 fluence of a particle of iron on each of those elementary princi- 

 |iles united to the copper. The play of affinities which enables 

 tiie particle of iron to strip the particle of copper of the whole 

 of its oxygen and volatile sulphurous acid, so as to leave it in its 



pure 



