Soap Bubbles
and the Forces which Mould Them

38 SOAP-BUBBLES, AND climb up the sides of the glass, then to gather into drops, and to run down again, and this goes on for a long time. This is explained as follows:—The thin layer of wine on the side of the glass being exposed to the air, loses its alcohol by evaporation more quickly than the wine in the glass. It therefore be- comes weaker in alcohol or stronger in water than that below, and for this reason it has a stronger skin. It therefore pulls up more wine from below, and this goes on until there is so much that drops form, and it runs back again into the glass, as you now see upon the screen (Fig. 14). There can be no doubt that this movement is referred to in Proverbs xxiii. 3.1 : “Look not thou upon the wine when it is red, when it giveth his colour in the cup, when it moveth itself aright.” If you remember that this movement only occurs with strong wine, and that it must have been known to every one at the time that these words were written, and used as a test of the strength of wine, because in those days every one drank wine, then you will agree that this explanation of the meaning of that verse is the right one. I would ask you also to consider