G. Barns — Decay of Ionized Nuclei. 425 



It makes no difference how the small efficient nncleation is 

 produced, whether by weak radiation, or by decay (time loss) 

 from a larger nncleation, or by small exhaustion catching but 

 few nuclei. 



The data of the fog chamber may be explained by postulat- 

 ing the absorption coefficient c so that if a be the number 

 generated per second —cln/dt— —a + cn + bn' 2 . In such a case, 

 if b is 10~ 6 the order of the corresponding decay of ions as 

 found by condenser, and if c is of the order of 3*5 XlO -2 , the 

 results of the fog chamber are closely reproduced for all 

 values of nucleation. 



A similar theory may possibly be extended to include the 

 absorption of phosphorus nuclei, carried by an air current 

 through thin tubes of different length and section (absorption 

 tubes). 



Finally it is improbable that the constant c should be 

 introduced by a systematic error in the standardization. of the 

 coronas of cloudy condensation. 



Brown University, Providence, E. I. 



