[miller] , 



CHEMICAL LABORATORY RESEARCHES 



273 



atmospheric pressure passes through a glass wall one sq. cm. in 

 area and one mm. thick into a vacuum. 



The several values given for each temperature were obtained on 

 different samples of silica glass. We also observed that helium 

 would pass through pyrex glass at 610°C. 



These experiments were carried out under the direction of 

 Professor J. B. Ferguson. 



Stability Relations of the Lower Oxides of Iron 



By D. M. FiNDLAY, B.A., and I. Hoover 



Presented by Professor W. Lash Miller, F.R.S.C. 



This is an extension of the work reported last year by Findlay, 

 Noble and Robertson. Known gas mixtures of hydrogen and water 

 vapour were passed for six hours over a suitable charge of iron or 

 iron oxide at a temperature of 750°C. Pure reduced electrolytic iron 

 was used as a starting point. For gas compositions having a ratio 

 of hydrogen to water vapour of 1.85 or higher the iron did not oxidize 

 while with compositions having a ratio of 1.76 or lower the iron did 

 oxidize. These results are a close check upon the recent work of 

 Chaudron which, though obtained by an entirely different method, 

 lead to a value of 1.85 for the constant of the iron-ferrous oxide 

 equilibrium at this temperature. Eastman's calculation of this 

 equilibrium from the measurements obtained on the system CO-CO2- 

 Fe-FeO leads to a value 2.25 for this temperature and he was some- 



18— C 



