CONTRIBUTIONS FROM THE WISLEY LABORATORY. 617 



alkaline carbonate. This substance has the power , of deflocculating 

 clay, and when present will prevent the action of lime upon it. Its evil 

 influence can only be counteracted by the addition of an acid or acid 

 manure like superphosphate of lime. 



Figure 180 shows the action of small quantities of lime (lime water 

 and calcium cyanamide) in flocculating clay. The clay falls rapidly 

 owing to its particles becoming joined into groups, while in the distilled 

 water they remain separate and in suspension. This action of lime on 

 clay, as is well known, takes place in the soil, and so renders clay soils 

 more open and workable, and calcium cyanamide has a similar action. 



