44 



Prof. J. N. Br^nsted and Prof. Gr. Hevesy on 

 Table IV. 



•action. 



Density 

 found. 



Density 

 calc. 



* 2 



. 1-000016 



1-000013 



3 4 



1-000024 



1-000024 



E 6 



. 1-000034 



1-000038 



R« 



. 1-000053 



1-000048 



»!o 



. 1-000079 



1-000075 



»14 



. 1-000134 



1-C00137 



3u 



. 1000153 



1-000152 



E l« 



. 100023 



1-000234 



Fraction. 

 D 



D 



Da 

 I>4 



D 5 



Density 



Density 



found. 



calc. 



0-999977 



0-999979 



0999953 



0-999956 



0-999933 



0-999935 



0-999911 



0999913 



0-999881 



0-999890 



As the figures found and calculated agree very well, 

 we may conclude, as will be more elaborately explained 

 later,that the evaporation of the mercury in our experiments 

 took place according to the theoretical supposition (reversed 

 proportion of the evaporation velocity to the square root of 

 the atomic weight). Further, that the separating process 

 of the mercury proceeds like that of a mixture consisting of 

 equal parts of two pure elements with the atomic weights : 



M! = M z - (1 4- A) = 200-6 . 1-0070 = 202-0, 



M 2 = M t -(1-A) = 200-6.0-9930 = 199-2. 



The results are also represented in fig. 4, exhibiting 



clearly the fulfilment of the requirement of a rectilinear 



interdependancy between the density and In— as follows 



from equation (7). 



As already mentioned, the above calculation presupposes 

 that the two constituting pure elements are present in the 

 mix-element in equal atomic proportions. If this sup- 

 position is omitted, there is an infinite number of M x and 

 M 2 values which are compatible with the value of M», 

 and corresponding to each of these cases a separate shape 

 of the separation curve (representing the interdependance 

 between the density d r and the volume of the residue) 

 is furnished. For* evaluating this fact in determining 

 the atomic weights, it is necessary, however, to consider 

 a longer portion of the curve than the one corresponding to 

 our experimental results. If we only consider the result of 

 the first separating operations, practically coincident curves 

 may be found also where the number of atoms and therefore 

 also the atomic weights of the two pure elements in the 

 mixed element vary. In order to further illuminate this 

 point, we proceed from the expressions (8) and (9) repre- 

 senting the atomic weight of the unchanged mix-element, 



