16 Mr. H. Kamage. Relations of Spectra, Densities, [Nov. 7. 



Many of the chemical and physical properties of these elements have 

 been considered, and the only common property yet discovered is con- 

 nected with the atomic volume. 



The atomic volumes of the two elements of higher atomic weights in 

 each group are almost identical. 



If it should prove that the two lines of barium do not correspond to 

 the strontium and calcium lines, we may find that the remarkable 

 curves joining the lines of copper, silver, and gold are connected with 

 the valency of these metals. The curve of melting points takes a 

 peculiar form also in these three metals. 



(4.) Intersection of the Lines connecting Homologous Doublets and Triplets. 



Kydberg* denoted by v the difference in oscillation frequencies : 

 (1) between the members of doublets; (2) between the two more 

 widely separated lines in triplets. He made the following observa- 

 tions : — 1st. " The value of v increases in special families with increase 

 of atomic weight." 2nd. " The constant v is, without doubt, a very 

 complicated function of the atomic weight." 



These observations were made entirely on the subordinate series of 

 lines, and he found that the values of 10 3 y/P 2 (where P = the atomic 

 weight) were a periodic function of the atomic weight. He has given 

 a more complete diagram of this in his paper to the Congres de 

 Physique, Paris, 1900. 



Rydberg's first observation is very clearly shown on my diagrams. 

 We learn further from them that in special families the value of v is 

 largely dependent upon the atomic mass, and that the function is 

 closely related to the square of the atomic mass. Plate 2, drawn 

 from these squares, shows that the lines which connect corre- 

 sponding members of homologous doublets and triplets approach one 

 another as the atomic mass decreases and intersect on the line of zero 

 atomic mass. This is true in every case studied, both in the subordi- 

 nate series, with constant differences of oscillation frequency, and in the 

 principal series of potassium, rubidium, and cesium, and in isolated 

 doublets. 



It is evident that the points of intersection of these connecting 

 lines cannot be absolutely determined, and a large personal element 

 may be introduced in some cases. This personal element cannot, 

 however, be large in the potassium and aluminium groups, where the 



* ' Kongl. Svenska Yetensk. Akad. Hand].,' 1890, vol. 23, No. 11. 



Atomic 

 volume. 



Atomic 

 volume. 



Copper 7 ■ 2 

 Silver 10 

 Gold 10 



Calcium 25 

 Strontium 35 

 Barium 36 



