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side of the line VY where the point D is situated and decreases 
when starting from F towards the other side of the line YFY. 
Hence, if a liquid proceeds along the line £D or FM, or FZ the 
vapour pressure increases starting from #’; if it proceeds along the 
line FZ, or FG or FE the vapour pressure decreases from /’. Only 
in the direction of F towards X or towards ) the vapour pressure 
remains at first unchanged. 
It will be easily perceived that these considerations are in harmon) 
with fig. 1. For the closed curves drawn in fig. 1 are the boiling 
point lines of the solutions saturated with F’. each curve, therefore, 
applies to a definite constant pressure. As the pressure becomes higher, 
these curves draw nearer to J/ to tinally disappear in this point. 
Of course, it may happen also that on increase of pressure a curve 
moves away entirely or partially from J/ to again draw nearer to 
M at a further increase of pressure. In the point F this, however, 
is not the case; we have already demonstrated that the part of the 
boiling point line passing through # situated in the vicinity of / 
moves on increase of pressure towards J/, and on reduction of pressure 
away from J/. 
x 
VY Fig, 2. 
part FZ lies, therefore, at the same side of XF} where the point 
D is situated; the part FZ, lies, therefore, at the other side. Perpen- 
dicularly on the line ZZ, we place the pressure axis, hence the 
vapour pressures of the liquids saturated with /’of the line ZEZ,. As 
In fig. 2 the line ZFZ, represents the same line of fig: 1; the 
