and the Constitution of the Atom, 277 



electric conductive capacity as mentioned in Paper I. should 

 vary in a similar way as n 2 . 



Let us, e.g., consider the elements for which q=-l, and 

 which follow immediately after an inert gas. These ele- 

 ments are Li, Xa, K, Rb, and Cs. The curve of Benedicks 

 (Paper I., fig. 3) shows a gradual increase of the conduc- 

 tive capacity indicating an increase of the quant-number. 

 From the X-ray analysis we know that when we come 

 to elements which give the L-radiation there is a second 

 ring with quant-number 2, which has 7 electrons. 



This result might indicate that the surface ring of the 

 elements of the first short period had the quant-number 2, 

 but we must also be aware of the possibility that some 

 change of the quant-number of the second ring may have 

 taken place, or we cannot be sure that also the elements 

 before Krypton have a second ring of 7 electrons with 

 quant-number 2. The very large increase of electric con- 

 ductive capacity from Li to Xa would be best accounted for 

 by assuming that the surface electron of Li had quant- 

 number 1. In that case the conductive capacity of the 

 elements considered should vary as the numbers : 1, 4, 9, 

 16, 25. 



These numbers give, at any rate, variations of the right 

 order of magnitude. In fact, the conductive capacity of Cs 

 is about exactly 25 times as large as that of Li. 



But we ought not to lay too much stress on this coinci- 

 dence, for the conductivity may be influenced by many 

 other causes. 



Putting the quant-number for the surface electron of Li 

 equal to 2, the conductive capacities should vary as the 

 numbers 4, 9, 16, 25, 36. It should be remembered that 

 the constitution given to Fe and Ni, in deducing the values 

 of v A for the K-absorption edge, was in accordance with the 

 latter assumption. 



A special interest is attached to the elements Cu, Ag, Au, 

 which have a large conductive capacity and only one electron 

 in the surface ring. We notice a very marked increase from 

 Cu to Ag corresponding to an increase of quant-number ; 

 but for Au there is again a drop of conductive capacity, 

 which might indicate a drop of quant-number. It seems as 

 if the formation of the rare earth elements is accompanied 

 with some kind of condensation process. 



The atomic property which first of all suggests itself for 

 examination is the atomic volume, because we might expect 

 it to vary in a similar way as the radius of the surface ring 

 in such a way that a greater radius would give a greater 

 atomic volume. 



