388 7 he Absorption of K X-rays of Silver in Gases. 



(a) For the first two mixtures, /jl\ and jx 2 were measured, 

 pi and p 2 observed, and the value of the left-hand side oE the 

 equation was compared with that of the right : — 



Gases. 



Pressures 

 (mm. of Hg). 



V1P1+V2P2 



Right side 

 above equation. 



S0 2 



Air 



SO, 



Air 



C0 2 



Air 



CO., 



so.; 



739 

 710 



703 

 729 



741 

 700 



735 

 705 



5-52 

 5-28 

 5-50 

 5-53 



564 

 5-29 

 5-G3 

 554 



(b) In the experiment with methyl iodide and air, the 

 absorption due to the additional air was determined. 



Gases. 



Pressures. 



" air. 



/* air (deter- 

 mined above). 



CK3I 



Air 



CH3I 



Air 



Ill 

 1384 



94 

 1421 



•00066 

 •00065 



•00059 

 •00059 



The agreement is not so close as before, possibly because 

 the decrease of ionization due to extra absorption by the air 

 was difficult to measure. Owing to the chemical activity of 

 the iodide, it could not be mixed with denser gases like 

 sulphur dioxide which would give greater change in ionization. 



(c) For the chemical combination test, the sulphuretted 

 hydrogen (from iron sulphide and hydrochloric acid) was 

 found, on analysis over caustic soda, to contain 7*5 per cent, 

 of hydrogen. This was allowed for in the two mixtures, so 

 that in each case there was a small surplus of hydrogen. 

 The ionizations resulting after absorption in each mixture 

 were determined in quick succession. 



Mixture. Ionization. 



700 mm. SH., + 700 0+57H 661 



700 mm. SO, 4-700 H + 57H 66"5 



Excess of H estimated by 

 analysis. 



Excess ofH added. 



