C A PILLAR Y A TTRA CTION. 47 



calculated from the radius, r, and the observed 

 difference of levels, //, as follows : 



for example, if the liquid taken be water, with a 

 free-surface tension of seventy-five milligrammes 

 per centimetre, and r = '05 cm., h is equal to three 

 centimetres. 



Fig. 31, representing a drop of ink just breaking 

 away from the stem of a glass funnel, is drawn 

 from an instantaneous photograph kindly given 

 me by Mr. Graham of Skipness, Argyllshire. He 

 took it himself on an " Ilford quick plate," from 

 a drop of ink just breaking away from the stem 

 of a glass funnel. 



Many experiments may be devised to illustrate 

 the effect of surface-tension when two liquids, of 

 which the surface-tensions are widely different, 

 are brought into contact with each other. Thus 

 we may place on the surface of a thin layer of 

 water, wetting uniformly the surface of a glass 

 plate or tray, a drop of alcohol or ether, and so 



