Disintegration Products of Uranium. 



429 



UrY is the second a ray product in uranium. However, the 

 following consideration shows that such is not the case. If 

 UrY is the second product in equilibrium with uranium, its 

 ol ray activity should be equal to about one half the total 

 activity of uranium. Since the product shows a strong 

 ft ray effect compared with the « ray effect, the absorption 

 curve of uranium should indicate the presence of a large 

 proportion of the soft rays characteristic of the product. 

 However, the absorption curve (see fig. 6) of uranium in a 



Fia:. 6. 



-> _ I 



. , , , 1 1 ! 



| ~l M i ll !■ 



i r I ■ — u ~7 — r 



, i I l i I L__J J I . _J ! 



/s x.o ss jo- js 4# 4s jo js Co cs yo is 



Thicknesses of aluminium, one foil equivalent to 

 about 0*5 cm. of air. 



thin layer shows that besides a rays only the rays of UrX 

 can be detected. Consequently it does not appear probable 

 that UrY is the second product in uranium. 



In considering the possible position of this product in the 

 uranium series, several factors have to be taken into con- 

 sideration. The evidence indicates that the new product is 

 not transformed into UrX, for we have seen that the /3 ray 

 rise curve of uranium, from which UrX and UrY were 

 separated by the ferric method, is quite normal in its initial 



