397 



Then C' is chosen so that agreement is obtained with the experimental 

 data'). Thus was found e. g-. when p is indicated in atmospheres: 



When we snbstitnte this value in our equation for log K,,, we find : 



C' = 5.8 

 and tlien equation (7) becomes : 



log K„ = - ^•^'^^ + log T + 5,8 .... (8) 



or 



log Kp = 



4,571 T 

 29100 



+ log T + 5.8 



(9) 



When we now calculate log Kp, by means of this equation for 

 temperatures between 400° 0. and 1000° C, we find what follows: 



TABLE I. 



When at the same temperatures and pressure we now also know 

 the values of log K for the equilibrium in the gas phase of the 

 different three-phase equilibria in the system Fe — CO — CO,, then 

 follow from equation (5) the values for the oxygen tensions at the 

 different temperatures. 



The values of log K for the equilibria Fe -f CO, ^ Fe -f CO, 

 3 FeO + CO, :^ Fe,0, f CO and 3Fe + 4 CO, ^ Fe,0, -f 4C0, have 



1) Abegg, Handbuch III, 2. 183. 



Proceedings Royal Acad. Amsterdam. Vol. XXI. 



26 



