THE TRANSFORMATIONS OF ELEMENTS 549 



There are several difficulties in the way of accepting such a 

 scheme. For example, radium D has given no indications of 

 any resemblance to the halogens ; on the contrary it strongly 

 resembes lead. Although such hypotheses must therefore be 

 put forward very tentatively, ( we can scarcely evade the con- 

 clusion that many higher members of the series have almost 

 coincident atomic weights, while there are several cases of 

 at least two elements occupying one space in the table. Thus, 

 considering the radium and thorium products alone, their 

 emanations are both inert gases strongly resembling the argon 

 gases. To move one a space higher in the series, the difference 

 in their atomic weights must be at least 25. If the hitherto 

 published chemical work on the atomic weight of radium is 

 in any way near the truth, this cannot be the case. Similarly 

 radium F must have an atomic weight less than radium, and 

 it closely resembles bismuth in all its properties. If the 

 atomic weight of radium is 226*5, it seems certain that bismuth 

 and radium F must occupy the same space. There are only 

 two other possibilities. A somewhat similar table, put forward 

 by Meyer and Schweidler in 1906, assumes that uranium con- 

 tains in reality a second element of much greater atomic 

 weight, about 260, and that radium has the corresponding 

 weight 255. In the second place, disintegration may result in 

 the combination of two or more atoms of the product, giving 

 an element of higher atomic weight ; in this case, the active 

 elements will not appear in consecutive series in the periodic 

 table. 



The second part of this paper will contain a full account 

 of radium and its emanation. 



The third part will include a description of the experi- 

 mental production of transformation or transmutation of 

 elements. 



