182 Mr. W. M. Hicks on some Effects of Dissociation 



increases and then decreases, whilst z decreases and a;' in- 

 creases continually as the temperature rises, so that the gas 

 has the same proportion of A or B at two temperatures. For 

 this type of gas the stability-cubic is easily solved ; for since 



dx dy dy dx dz dz dx dy 

 we may write the cubic in the form 



K — X, 



K — \, 



=0; 



one root of which is 



ax dx 

 and the others are found by the quadratic 



-1, 







h 



= 0. 



-p — -^=: — ■{4a33 + 2ai^)x^ + Aa^x + a^^z} , 



It may be noticed that 



df^_df2 



dx dx 



and is therefore a negative quantity. 



31. I have also worked out the case of a compound gas with a 

 diatomic molecule/ in which the masses of the components are 

 nearly equal (mi = 14, m2 = 16), the radii of action the same as 

 those of NN; CTO, and NO, and ^i = f 6^, 6^=^ 6^. The results 

 are exhibited by the curves in fig. 4. The thick black curve 

 A B represents the relation between the numbers of compound 

 molecules A B and the temperature ; the thin curves 00, 00^ 

 give the numbers of A A and B B molecules respectively, and 

 D, D^ those of the A and B atoms ; in each case the dotted 

 curve belongs to the B component. 



These curves show us at a glance what happens as the tem- 

 perature increases from zero. At zero the whole gas is in the 

 compound state. As the temperature rises, at first very little 

 dissociation takes place ; and then a small proportion of the 

 compound becomes gradually dissociated, but the dissociated 

 atoms chiefly recombine at once to form A A and B B mole- 

 cules. As the temperature still further increases to about ^ 6^, 

 the dissociation of A B takes place very rapidly, most of its 

 dissociated atoms now remaining so, but some still recombi- 

 ning to form A A and B B. At about \6qOV \ Oi the number 



