396 Interfacial Tension and Complex Molecules. 



mutual solubility. In this case the eutectic point corre- 

 sponds to a very low concentration, i. e. approaches very 

 closely to one of the ordinates. But such a point must exist 

 if the liquids are at all soluble in each other. It is obvious 

 that if the eutectic point exist 



must certainly hold true and the relation 



"12 = «1 — «2 



must necessarily be satisfied. 



Summary. 



1. A theory of molecular attraction has been developed. 

 The theory detailed above follows from the ordinary 

 modern representation of the nature of atoms and mole- 

 cules. Starting from this point of view, the phenomena of 

 molecular attraction depend on the same forces as chemical 

 affinity. 



2. A relation between surface tension and molecular 

 pressure has been deduced. 



3. It was deduced theoretically that the interfacial tension 

 a 12 is equal to the difference of the surface tensions against 

 the air of both superposed liquid layers a 1 — a 2 in equilibrium, 

 which is in agreement with experiment. 



4. Two superposed layers in equilibrium must be regarded 

 as solutions in the same dissolvant. 



5. They must contain an equal number of molecules per 

 unit volume (Avogadro's Law). 



6. Statement (5) is a result of formation of complex mole- 

 cules in the solution. 



7. The so-called monovariant systems may be obtained 

 without fulfilment of the requirements of the Phase Rule, 

 if the molecules of the component added combine with 

 those in solution without increasing their number. 



The author, in conclusion, wishes to express his sincere 

 thanks to Prof. Svante Arrhenius and Prof. Arthur Schuster, 

 both of whom have kindly read this paper and made valuable 

 criticisms and suggestions. 



26 Chester Square, 



