Mr. M. M. Pattison Muir on Chemical Classification. 2G3 



others. Now it is found that in the second and third sec- 

 tions of the curve of atomic vohimes (that is, in those sections 

 situated between the maxima lithium and sodium, and sodium 

 and potassium) the elements situated on the descending por- 

 tions of the curve are electro-positivCj while those on the 

 ascending portions are electro-negative. In the fourth, fifth, 

 and sixth sections^the maxima being potassium and rubi- 

 dium, rubidium and ccesium, and csesium and bismuth — we 

 find on each descending portion, first a set of electro-positive 

 elements, then a set of electro-negative elements; then ascend- 

 ing towards the next maxijnum point, we have first electro- 

 positive, and then electro-negative elements. But the electro- 

 positive or negative character of those elements which are 

 situated near a maximum point of the curve, is found to be 

 much more marked, as a rule, than the electro-positive or 

 negative character of those elements which are situated near 

 a minimum point of the curve. Thus, in the fourth section 

 of the curve, potassium and calcium are the electro-positive 

 elements placed at and next to the maximum point ; nickel 

 and cobalt, copper and zinc, are the electro-positive elements 

 placed at and immediately after the minimum point. IsTow 

 the electro-positive character is much more marked in the case 

 of potassium and calcium than in that of cobalt, nickel, copper, 

 and zinc. 



It would appear, then, that a well-marked positive or nega- 

 tive character is only possessed by those metals which have 

 comparatively large atomic volumes ; or, as it is expressed by 

 Meyer, " the aggregation of a large mass in a small space 

 appears incompatible with the development of a marked posi- 

 tive or negative character." A closer inspection of the posi- 

 tion of the various elements in relation to their electro-positive 

 or negative character shows that this character is much in- 

 fluenced, not only by the atomic volume of the individual ele- 

 ment, but also by the manner in which the atomic volume 

 changes from element to element. The electro-positive ele- 

 ments which are situated near a maximum point on the 

 curve, and between whose atomic volumes there is a com- 

 paratively large difierence, are more electro-positive in cha- 

 racter than those situated near a second maximum point but 

 possessed of atomic volumes between which there is a com- 

 paratively small difference. 



Again, it is evident that the absolute magnitude of the 

 atomic weight influences the positive or negative character of 

 the elements. Thus, in the third section of the curve, on ihot 

 ascending portion are found phosphorus, sulphur, and chlo- 



