894 Dr. A. C. Orehore on 



possible interpretation to place upon the experimental obser- 

 vations of Rutherford, it shows that the unknown atom may 

 have been that of fig. 2 obtained from both nitrogen and 

 oxygen during its disintegration. 



The exact agreement between Rutherford's result for 

 nitrogen and the model shown for N is truly astonishing when 

 it is borne in mind that he has found experimentally that the 

 distance from the centre of the N atom to the centre of the 

 H atoms in nitrogen is just two diameters of the electron 

 itself. The reason why there has been found to be a critical 

 experimental distance within which the law of scattering 

 suddenly changes is made apparent by this theory. Also 

 the reason why the hydrogen atoms are driven ahead without 

 much scattering within this critical distance is because two 

 electrons, the one in the hydrogen atom and the other in the 

 alpha particle, come into actual collision and cannot inter- 

 penetrate each other. v 



Note added February 1922. 



Since the manuscript of this paper was submitted in August 1921 

 experimental results of importance have been published. A rule has 

 been adopted for determining- the atomic number of the atom from the 

 models which necessitates some changes in fig. 1. The rule may be 

 stated as follows:— the atomic number is equal to the total number 

 of connecting electrons in the atom, provided one is counted for hydro- 

 gen and two for helium, and that one be counted in the more complex 

 atoms when a single doublet, that is either a hydrogen atom or an alpha- 

 particle, occupies the exact centre of the atom, and that two is counted 

 when a helium atom occupies the centre. 



According to this rule the models shown as Li-1, Gl-1 and B-l in 

 fig". 1 do not have the proper atomic numbers for these elements, but 

 all of the others satisfy this rale. The charges of 5 e and 6 e with 

 masses of 6 and 9 respectively in accordance with Table I. are thus 

 never required. A new model for Li-1 having perfect symmetry about 

 its centre is shown in fig. 1 a, having mass 4+2x1 '008 = 6*016, and 



Fig. 1 a. 



atomic number three according to rule because there are two connecting 

 electrons and an alpha-particle at the centre for which one is to be 

 counted, making three. The isotope Li-2 of fig. 1 may remain as the 

 principal isotope of Li having mass 7, for it satisfies the rule giving 

 atomic number three. 



G. P. Thomson * reports glucinum as an atom of mass 9, and states 



* Phil. Mag. Nov. 1921, p. 859. 



