38 POPULAR LECTURES AND ADDRESSES. 



water-surfaces under different conditions as to 

 capillarity ; the scale of the drawings for each set 

 of figures is shown by a line the length of which 

 represents one centimetre ; the dotted horizontal 

 lines indicate the positions of the free water-level. 

 The drawings are sufficiently explicit to require 

 no further reference here save the remark that 

 water is represented by the lighter shading and 

 solid by the darker. 



We have been thinking of our pieces of rigidified 

 water as becoming suddenly liquified, and conceiv- 

 ing them enclosed within ideal contractile films ; 

 I have here an arrangement by which I can 

 exhibit on an enlarged scale a pendant drop, 

 enclosed not in an ideal film, but in a real film of 

 thin sheet india-rubber. The apparatus which 

 you see here suspended from the roof is a stout 

 metal ring of 60 centimetres diameter, with its 

 aperture closed by a sheet of india-rubber tied to 

 it all round, stretched uniformly in all directions 

 and as tightly as could be done without special 

 apparatus for stretching it and binding it to the 

 ring when stretched. 



