b(]i 



Mr. E. P. Adams 07i 



tlio sensitiveness was the same at each reading. The follow- 

 ing table gives the results, beginning at the time when the 

 maximum conductivity is reached : — 



Time to leak 30 divisions 



366,000 

 401,000 

 494,000 

 381,000 

 372,000 

 573,000 



The accompanying figure is plotted from the above table. 

 The ordinates are the numbers in the third column, which 

 are proportional to the conductivity of the gas, and the 

 abscissae are the times in hours. 



Hours. 



in seconds. 



Keciprocals 







53-2 



188 



16-7 



62-7 



160 



40-4 



77-6 



129 



64-8 



92-7 



108 



88-9 



116-3 



86 



139-6 



190-0 



53 



160-8 



217-9 



46 



200 



160 



120 - 



&Q 



40 



\0 



40 



SO 



120 



160 Hours 



Assuming, as in the case of radium emanation, that the 

 decay of the radioactivity can be represented by the formula 



the values of 1/X corresponding to the successive intervals 

 are given in the fourth column of the above table. The 

 tim« in this formula is expressed in seconds. Giving these 



