The vapoui' contains only one component. 



We assume that of the components A, B, and C the first two 

 are extremely little volatile, so that |)ractically we can say that the 

 vapour consists onl}' of C. This shall e.g. be the case when A and 

 B are two salts and C a solvent, as water, alcohol, benzene, etc. 



Theoretically the vapour consists always of A -\- B -\- C ; the 

 quantity of A and B, however, is generally exceedingly small, 

 compared with the quantity of 6', so that the vapour consists prac- 

 tically completely of C. 



When, however, we consider complexes in the immediate vicinity 

 of the side AB, circumstances change. A complex or a li((ui(l 

 situated on this side has viz. always a vapourpressure, although 

 this is sometimes inmeasurably small; consequently there is also 

 always a vapour, consisting only of A -f B without C. When we 

 take a complex in the immediate vicinity of the side AB, the 

 quantity of C in the vapour is, therefore, yet also exceedingly small 

 in comparison with the quantity of A -\- B. 



Considering equilibria, not situated in the vicinity of the side 

 AB, we may, therefore, assume that the vapour consists only of 6'; 

 when, however, these equilibria are situated \n the immediate 

 vicinity of the side AB, we nmst also take into consideration 

 the volatility of A and B and we must consider the vapour as 

 ternary. 



Considering only the occurrence of liquid and gas, as we have 

 formerly seen, three regions may occur, viz. the gasregion, the 

 liquid-region and the region L — G. This last region is separated from 

 the liquid-region by the licpiid-curve and from the vapour-region 

 by the vapourcurve. 



As long as the liquid-cui-ve is not situated in the immediate 

 vicinity of AB, this last curve, as a definite vapour of the vapour- 

 curve is in equilibrium with each liquid of the liquid-curve, will 

 \)Q situated in the immediate vicinity of the anglepoint C. Therefore, 

 the gas-region is exceedingly small and is I'educed, just as the gas- 

 curve, practically to the point C. Consequently we distinguish within 

 the triangle practically only two regions, which are separated by the 

 liquid-curve, viz. the liquid-region and the region L — G ; the first 

 reaches to the side .4i^, the last to the anglepoint C. The conjugation- 

 lines liquid-gas come together, therefore, practically all in the point C. 



When, however, the liquid-curve comes in the immediate vicinity 

 of the side AB, so that there are liquids which contain only exceed- 

 ingly little C, then in the corresponding vapours the quantity of 

 .1 and B will be large with respect to 6'. The vapour-curve will 



