38 T ronxactwns. 



As Dr. Ewan has shown, the pressure of oxygen atoms should be pro^ 

 portional to the square root of the pressure of oxygen if the law of mass 

 action holds strictly, and a state of equilibrium is assumed, for there is 

 equilibrium between the oxygen atoms formed and the oxygen molecule. 

 The equation therefore becomes 



K'C(„,) = C(,.) X C(„) = C(,,)^ 

 where C(„2) and C(„) represent the concentrations of oxygen molecules and 

 atoms respectively. 



From this, then. 



C(„) = K'CM,,.), 

 or the pressure of the oxygen atoms varies as the square root of the pressure 

 of the oxygen molecules. The actual value of K' will undoubtedly be very 

 small, as the nimiber of oxygen atoms present can hardly be great even 

 under the most favourable conditions. 



In integrating the equation 



we put }/ = h — X ; fo = ^^ — ^a-. 



This gives — '^-^^^^ = K (& — x)^ [a — 2x), 



or ~j = Is. {h — x)'^ {a — 2x), 



and integrating it gives 



K^ - - , (6-1)* ^°- (,_,)* + (,_!)! + ^«^^«^^"*' 

 or, writing the logarithm to the base 10, we get 



Kt 1 , ib-x)^ ~(b-'^^- 

 •2.30= - y (6-^)4 ^°S>°^^ a^/, :y. + constant. 



The constant is obtained from the condition that x = o v/hen / = o, and the 

 equation is therefore 



1 (6_,.)i _(?,_£;)* 1 6*-(6-|)^ 



^'^ - - ,(,_!)* log. ^,::^^x^^ + .(._|)^ log. ^^-^-^ 



where K' = ^ -30" 



The values of K' given in the tables are calculated by means of this 

 equation, and in each case are multiplied by 10^. 



Experimental Work. 



There seems to be nothing more clear from my experiments than that 

 the action is extremely susceptible to the influence of accelerating and 

 retarding influences. Much time was lost in the early part of the work 

 through the sample of aldehyde, prepared by repeatedly redistilling a 

 stock sample, containing paraldehyde. The result of using this sample was 

 that the action would not go on at a rate at all comparable with that 

 which Dr. Ewan observed, though otherwise the conditions were the same. 

 When compared with the results obtained later on with a pure samjile the 

 difference is at once apparent. 



