Outer 



Radium Emanation by Coconut Charcoal. 785 



IV. 



Experiments with two charcoal tubes in series to find out how 

 the relative amounts of emanation absorbed by each of the 

 tubes depend on the duration of the exposure. 



The silica tubes were connected up as follows : — 



--*>Kadium Solution^* 1 metre of calcium chloride-**Tube 13 -a-Tube A-^Gauge A-*Pump. 



Table III. 



Duration 



of 

 Exposure. 



Amount of 

 Emanation 

 caught by B. 



Amount of 

 Emanation Rat 

 caught by A. 



A 



10 >B- 



Means. 



3 hours. 



5-0 



•2 



04 



I 





>» )> 



4-8 



•7 



14 





•10 



>> n 



4-9 



•6 



12 



J 





5£ hours. 



7-1 



1-7 



24 



} 



•20 



)> >5 



8-0 



1-3 



16 



11 hours. 



122 



34 



28 





•28 



22 hours. 



18-5 



111 



6* 







>> 51 



224 



70 



31 





•31 



44 hours. 



29-9 



130 



45 



! 



•40 



„ „ 



349 



12-4 



36 



* Neglected in finding the mean. 

 Fig. 2. 









Tubes in series 













— >B-* 



— - ' o 



A-> 







•2 





0^^^^ 











< / 













o 







i | 







i 





b + 



3 IZ 1 



6 20 a 



.♦ Z8 Z 



K. 36 1 



IO 4* 



EXPOSURE(Hou« s ) 



and the air sent through it at a constant rate (*5 litre 

 per minute). The radium solution used contained f of 

 3*14 x 10" 9 gm; radium. 

 Phil. Mag. S. 6. Vol. 20. No. 118. Oct. 1910. 3 F 



