EARTH SATUEATED AVITII MINERAL MATTER. 143 



lime for each square decimetre of the field. Calculated 

 upon a square decimetre ( = 15vV square inches) of surface 

 and a depth of 20 centimetres ( = 7-8 inches), these 25 

 cubic centimetres constitute the eightietli part of the 

 entire mass of earth. 



The experiments of Naegeli and Zoeller, before des- 

 cribed, furnish a good example of this kind of manuring. 

 TJie manure consisted of turf, partly satm^ated with nutri- 

 tive substances and mixed with three volumes of turf almost 

 absolutely unfi-mtful ; this constituted a soil of the same 

 degree of fertility as good garden mould. 



Such an addition of earth saturated with mineral con- 

 stituents does not usually take place ; but the ordinary 

 method of manuring comes exactly to the same result. 

 The field is di-essed with hquid or sohd manuring matters 

 containing nutritive substances, which combine imme- 

 diately if in solution, gradually if requiring a certain time 

 for solution, with the earthy particles with which they 

 are in contact, and saturate them ; and it is properly 

 this earthy saturated ivit/i manuring matters on its outer- 

 most surface or in the inner parts with ivhich the farmer 

 manures^ i.e. with which he replaces the mineral con- 

 stituents withdrawn from the soil. 



Experience has taught the agriculturist which parts of 

 the soil may be enriched with nutritive substances most 

 profitably for himself, or rather for his plants ; and it is 

 remarkable in the highest degree how he has found out 

 the proper method of manuring in accordance with the 

 nature of the intended crop, the soil, and the period in 

 which the plants are developed ; also whether to proceed 

 by simple top-dressing or by ploughing the manure in to a 

 greater or less depth.* 



* ' Joum. of the Royal Agric. Soc. England,' t. 21, p. 330. 



