EAETH SATURATED WITH MINERAL MATTER. 145 



scribed, furnish a good example of this kind of manur- 

 ing. The manure consisted of turf, partly saturated 

 with nutritive substances and mixed with three volumes 

 of turf almost absolutely unfruitful ; this constituted a 

 soil of the same degree of fertility as good garden 

 mould. 



Such an addition of earth saturated with mineral 

 constituents does not usually^take place ; but the ordi- 

 nary method of manuring comes exactly to the same 

 result. The field is dressed with liquid or solid manur- 

 ing matters containing nutritive substances, which com- 

 bine immediately 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 earth, saturated with manuring matters 

 on its outermost surface or in the inner parts with which 

 the farmer manures, i. e. with which he replaces the 

 mineral constituents withdrawn from the soil.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.* 



In these respects the successes of the agriculturist 

 would be still greater if the nutritive substances con- 

 tained in the manure principally used, namely, farm- 

 yard manure, were more uniformly mixed and distrib- 

 uted, because this would lead to a more uniform distri- 

 bution of them in the soil. 



Farm-yard manure is a very irregular mixture of 

 decaying straw and vegetable remains, combined with 

 solid animal excrements, the latter constituting the 

 smaller portion of the whole mass : it is soaked with 

 fluids which hold ammonia and potash in solution. If 

 a hundred samples be taken from a hundred different 



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



7 



