Orientation of molecules in the condensed and gaseous films

Orientation of molecules in the condensed and gaseous films. Summarizing the evidence given above as to the arrangement of the 

The third evidence is that it is often possible to change a coherent film, condensed or liquid-expanded, into a gaseous film simply by introducing into the molecule a second point of attraction to the water, some distance from the first. These two water-soluble groups would naturally make the molecules lie flat. Thus the following form good gaseous films  

The corresponding compounds with a hydrocarbon group or hydrogen atom instead of the water-soluble group are cither coherent films or vapour-expanded with much more lateral adhesion between the molecules. 

---