44 On Actinium and its Successive Products. 



It is seen that there is a very striking similarity between 

 the number and nature of the changes for actinium and 

 But the periods of decay, the radioactive, chemical 



tho 



Tium. 



ACTIN— - ACT/A/ X- -ACT £ MAN.- -ACT/ N. A- -ACT/N B- ^\CT/N. C 

 ? /oac/cVjys .=-7 s«c. .3 fern in ismin 



and physical properties of the products of actinium all point 

 conclusively to the fact that we have in actinium a distinct 

 chemical element. 



Whilst writing this paper, the December number of the 

 Jalirbuch fur Radioaktivitat und JElektronik was received con- 

 taining a paper by Giesel on Emanium*. In this paper 

 Dr. Giesel gives an account of his investigation, in which he 

 finds that it is possible to separate from emanium by preci- 

 pitation with ammonia a small amount of very strongly active 

 substance. The method of separation employed by him was 

 then identical with the method I have used. I cannot, how- 

 ever, compare quantitatively my results with his, inasmuch 

 as Dr. Giesel does not publish any measurements. 



A short account will now be given of some experiments 

 which are still in progress on the nature of the (3 and y rays 

 of actinium. 



* Giesel, "Untersuchungen liber das Emanium (Actinium)," Jalirbuch 

 f. Radloakt. vol. i. pp. 375-358. 



