C 565 3 



923. Action of lime. It is not', however, by way of direct 

 supply of food to plants that liming proves of benefit to the 

 soil. Liming alters the texture of the soil either for good or 

 for evil. In some soils it acts as a mortar and renders it 

 hard, especially if slaked lime is applied as; a thick, smooth' 

 paste on soil in hard condition. In other soils e. g. in peat, 

 constant liming may interfere with capillary action by making 

 the soil too open. Ordinarily/ however, a soil rich in lime main- 

 tains a better capillary action, and liming irfrproves the texture 

 of soilsby making them more porous. Lime exerts another kind 

 of physical action which may be called flocc.ulation, finer par- 

 ticles being converted into coarser ones. Schlcesing disco- 

 vered that 2 parts of lime in the form :of ^chloride., nitrate or 

 sulphate of ealciuifi immediately caused flocculation in 10,000 

 parts of a turbid liquor that contained a good deal of clay, 

 that flocculation was perceptible when the proportion was 

 reduced *o i in 10,000, but that \ a part of lime had no effect 

 on the liquor in question even in the course of 6 weeks. 

 Another experiment may be tried to^bring out the nature of 

 the influence exerted by lime on plastic soils. Let a quantity of 

 tough clay soil be worked into a plastic mass with water and 

 let a portion be then dried, the result will be a mass of stony 

 hardness. To another portion of the paste add half a per 

 cent, of caustic lime and a diminution of plasticity will be 

 obvious at once even when the mass is wet. On drying this 

 mass will fall into crumbs at a mere touch. By liming, clay 

 soils are made warmer, mellower, and of better tilth. This 

 lightening effect lasts for years and is - never entirely 

 lost. 



924. Another effect of lime^is to set free for the use of 

 crops, potash, ammonia and magnesia from hydrated double 

 silicates. Experiments have shown that gypsum does this 

 better than lime. 



925. Lime in a caustic condition has a highly beneficial 

 effect on peaty and boggy soils (/. e, soils rich in humus) and 



