188 
j are, however, very independent of the pressure and shift at a larger 
pressure, the first towards the left, the second to above. 
Lowering of the pressure therefore causes extension of the existable 
iron region inclosed by the lines c,7 and d. Increased pressure causes 
this region to shrink. 
Of the lines present in this figure d is known from the research 
of Bovpovarp and others’), 6 and c have been determined by Baur 
and GLAESSNER *). between the temperatures 400° and 950°. The line 
h has according to these measurements a maximum of 46°/, CO at 
500° and falls on increase of temperature to 23°, CO at 950°. The 
line c has a minimum at 675° and 58°/, CO and rises afterwards 
to 940° and 75°/, CO. The point of intersection // is for 1 atmos- 
phere at 647° and 37°/, CO, //1 at 685° and 59°, CO. 
As to the points V//Z and /X and the lines 7 and / no mention 
is made thereof by Baur and Graussner. Probably a part of the 
points determined by them will belong not to c, but to line /. As 
however they do not state any analysis of the solid phase, this 
cannot now be decided. 
If the pressure is increased to above that of the quintuple point 
0, the lines /// and V1/ (Fig. 8) are no longer cut but instead 
thereof V/. The existable region of Fe then disappears and the section 
becomes as shown in Fig. 11. 
Co = The lines ¢ and 7 have 
£ SO menb- disappeared in this section 
/kristafben and with these the equili- 
a ae bria 7/7, 1 X'and: VAT In 
the place thereof arrives 
it the equilibrium WV/. FeO 
bod so Sel” now does not pass into 
72, 0, Da iron on reduction in contact 
Co, + with carbon, but directly 
forms mixed erystals. 
Fig. 11. ) 
An investigation to decide the most important points in these 
equilibria is now in progress. The results will be communicated in 
due vourse. 
Delft. Laboratory inorg. and phys. chemistry 
Technical University. 
alec ps il 
2) Z. f. physik. Ch. 48, 354 (1903). 
