782 Mr. J. Satterly on the Absorption of 



with a radium solution in series with one of the tubes, and 

 exposures were made of different periods but with air-streams 

 of the same strength (*5 litre per minute). The radium 



solution used contained 



3'14 

 5 



x 10 9 om. of radium. Some- 



times the solution was in series with Tube A, sometimes with 

 Tube B. Tn calculating the last column, allowance has been 

 made for the tact that Tube 15 absorbs about 10 per cent, 

 more than Tube A*- 



Table I. 



From the figures in the second and last columns the 

 following curves (fig. 1) have been plotted. If for exposures 

 of all the periods named the fraction of emanation absorbed 

 was the same, the curves would be practically straight. 

 (There would be a slight falling away from the straight line 

 owing to the decay of the emanation : this, however, is very 

 slight, as is evidenced by the dotted line in fig. 1, which 

 represents on an arbitrary scale the growth of radium 

 emanation from a quantity of radium.) 



Sinvlar experiments made in July and August f with a 

 3-hours exposure and a solution of 3*14 x 10~ 9 gm. radium 

 gave 4*5 for tube B and 4*4 for tube A. Therefore, assuming 

 as is proved in I. that the amount absorbed from these solu- 

 tions in a short time is proportional to the strengths of the 



* See Phil. Mag. July 1910, pp. 15, 17. 

 t Phil. Mag. July 1910, p. 27. 



Date, 

 1909. 



Period 



of 



exposure 





Air alone. 



: 



A 



i.r-r- Solution. 



Tube. 

 A 



Vol. 



of air 



in 

 litres. 



Emana- 

 tion 

 caught. 



Tube. 



Vol. 

 of aii- 

 in 

 litres. 



i Total 

 Emana- 

 tion 



caught. 



Emanation 



caught 

 from the 

 solution. 



Oct. 2fi 27. 



224 hrs. 



633 



11 



B 



660 



47 



4-7- 1-2=3-5 



„ 27-28. 



21 „ 



B 



607 



•9 



A 



040 



41 



41- -8=33 



: „ 28-29. 



15 „ 



A 



452 



•7 



B 



448 



36 



36- -7=29 



Nov.2 



7 „ 



A 



212 



1-3 



B 



214 



3-2 



3-2-P4 = r8 



°-3 



21 „ 



B 



647 



22 



A 



657 



5-2 



5-2-2-0=3-2 



„ 3-4 ... 



21 „ 



A 



637 



2-6 



B 



631 



7 2 



7-2-2-9=38 



„ 5 



7 ,, 



B 



211 



•6 



A 



213 



20 



20- -6=1-5 





7 „ 



A 



210 



11 



B 



209 



28 



28— 11 = 1-7 



