834: S. Kinoshita, S. Nishikawa, and S. Ono on Amount 



Since the life of the thorium emanation is extremely short, 

 its distribution in the atmosphere will be far from being 

 uniform. However, on the assumption that its amount p«r 

 unit volume is the same at equal heights, we get similarly the 

 expression V for the current due to the thorium deposits, as 



in which X A ' denotes the constant of transformation of 

 thorium A, and B/ the ratio of the effective ionization to the 

 total ionization of the a-particles emitted from thorium B 

 and thorium C. At the present stage of accuracy we may 



put vr =1. 



As is seen from (a) and (d), Art. 3, 



1 = 4-0(3 x 4-52 x 10" 13 = 1-84 x 10" 12 amp., 



r = l-08 x 4-52 x 10" 13 = '49 x 10~ 12 amp., 



for the upper wire, and 



1=4-28 X 4-52 xl0~ 13 = 1-93 xlO" 12 amp., 



F = 2-20 x 4-52 x 10" 13 = -09 x 10" 12 amp., 



for the lower, on the average. 



Calculating from the values of these and /u's and the 

 following data : — 



7e = 1*74x10 5 *, 7e ' = 2-02 Xl0 3 t, 



ry A =l-87x 10 5 *, 7 i/=l*91 x 10 5 t, 



7c -2-37xl0 5 *, 7c ' = 2'27xlO r 't, 



A E = 2'08x 10- 6 (sec.-'), Xe' = 1"31x 10~ 2 (sec.- 1 ), 

 \ A = 3-85xlO- 3 (sec k -^),X A ' = l-8 x 10~ 5 (sec." 1 ), 

 Z = 2,000 cm., ^ = 4-65xlO- 10 E.s. units t, 



k = l%\ ?o = 2-5§, « = 3420 e=l-60 x 10" 6 L 



* Geiger, Proc. Roy. Soc. vol. lxxxii. July 1909. 



+ These values are* obtained by inter- and exterpolaticn from the 

 values of y E , yA, &c. 



t Rutherford and Geiger, Proc. Roy. Soc. vol: lxxxi. p. 162 (1908). 



§ This is the value calculated by* Eve (Phil. Mag. Jan. 1911) from 

 the data found by Wright (Phil. Mag. Feb. 1909). 



|| We have, for the present, taken the value of Townsend for dust-free 

 air (Trans. Roy. Soc. vol. lxxxi. p. 170). 



