THE SOIL 115 



culated for convenience of comparison to 100 parts of 

 soil. 



Fit a cork, with a hole in it, into a glass tube, about 

 f inch in diameter, and arrange a small piece of linen or 

 blotting-paper over the cork, inside the tube ; now pour 

 shot into the tube (see Fig. 16). The shot may be taken 

 to represent particles of soil with their air-spaces. Close 

 the opening in the cork with the 

 ringer, and pour water on the shot, 

 fully covering them. This condition 

 may be taken to represent soil from 

 which all the air has been displaced by 

 water. Remove the finger ; most of 

 the water will now drain away, but 

 some will be retained, by capillary 

 attraction, between the grains of shot. 

 From this experiment draw inferences 

 as to the relation of water to small 

 soil-particles. 



Place in a saucer a little water, to Fl ' 



which a few drops of red or black ink tention of water be- 



, , tween small particles 



has been added (merely to colour it), by capillary attrac- 



i j. e . f. tion. 



and dip one corner of a piece of 

 blotting-paper into the water : notice how the liquid 

 rapidly spreads through the whole piece. This is an 

 example of the action of capillary force. 



Take two small pieces of glass (about 3 or 4 inches 

 square) ; stand them upright in a saucer of water (which 

 may be coloured if desired) ; bring their edges together 

 on one side so that the pieces stand like a partly-opened 

 book standing on its edge (see Fig. 17). Gradually bring 



