CAPILLARITY. 213 



ing the bottom of the vessel and the lower surface of 

 the cork, the experiment may be made in water with 

 the same success as in mercury. 



Melt a small piece of stearine candle in a ladle, and drop some of 

 it upon an adhesion-plate placed horizontally, so as to form a 

 circle of not more than 15 mm diameter. Before the molten stearine 

 hardens, place upon it a round piece of cork, about 10 mm in 

 diameter, and from 5 to 10 mm high. After cooling, the cork 

 with the attached stearine is carefully detached from the plate by 

 gentle pressure from the side. The stearine gives to the cork a 

 surface which is not moistened by water, and the cork is required 

 because the stearine by itself is very little lighter than water ; 

 both together form a body which floats. Remove the sealing-wax 

 handle from the adhesion plate, and place the plate upon the bottom 

 of a capacious tumbler, in order to have as even a surface as possible ; 

 sprinkle some lycopodium over the plate, place the float of stearine 

 and cork with the flat side upon it, and fill the tumbler cautiously 

 with water, while the float is pressed very slightly to the plate by 

 means of a small rod. When the tumbler is full withdraw the 

 rod; the float, pressed downwards by the liquid, remains at the 

 bottom ; but if slightly displaced so that water may get underneath 

 it, the float rises immediately. 



Many solid substances are dissolved by certain liquids, 

 that is, they become themselves liquid if brought into 

 contact with them : sugar, common salt, gum arabic, 

 are thus dissolved by water, resinous bodies are dissolved 

 by alcohol, etc. The fact of the solubility of a solid 

 in a liquid is explained thus : the adhesion between a 

 solid and a liquid may be either less or greater than the 

 cohesion of the molecules of a liquid; in the case of 

 mercury and glass, the cohesion of the mercury is greater 

 than the adhesion between mercury and glass ; in the 

 case of water and glass, the cohesion of the liquid is less 

 than the adhesion between the liquid and the solid. 

 Now, it may happen that the adhesion between a solid 

 and a liquid is also greater than the cohesion of the 



