MANURES. 85 



It will be further observed, that even pure rain water iS capable of 

 rendering- soluble a considerable quantity of all those mineral con- 

 stituents which are found in the ashes of our crops, and therefore 

 are necessary to their growth. 



2. Filtration experiment made with the drainings of a dung-heap 

 composed of fresh mixed farm-yard manure. Having ascertained 

 in the previous filtration experiments, that a soil containing a good 

 deal of clay and lime is capable of removing from compound man- 

 uring substances all the more valuable fertilizing constituents, I 

 was anxious to determine to what extent soils deficient in both 

 clay and lime, possessed the property of retaining fertilizing sub- 

 stances from the drainings of dung-heaps. The composition of the 

 liquid used for this experiment is given above ; it is the same 

 liquid collected from a fresh dung-heap, which in a gallon con- 

 tained 1,357.T4 grains of solid matter. The soil selected for 

 experiment was a light, sandy, red-colored, very porous soil, con- 

 taining, as will be seen by the following analysis, only little clay, 

 and still less lime, but a good deal of organic matter. It was 

 submitted to a minute and careful mechanical and chemical analysis 

 and furnished the results embodied in the subjoined tables : 



I. Mechanical Analysis. 



Moisture, 3.45 



Organic matter, and water of combination, 13.94 



Coarse, white, quartz sand, 4Y.00 

 Fine, red sand, and a little clay deposited from water on 



standing five minutes, 19.82 



Coarse clay, deposited on standing ten minutes, 2.82 



Fine clay, deposited from water on standing one hour, • 6.30 

 Finest clay, kept in suspension in water, after standing 



longer than one hour, 6.6T 



100.00 



It appears from these results, that nearly half the weight of this 

 soil consists of pure white, coarse, quartz sand, which can be 

 readily separated by washing. The deposit which settled from 

 water, after five minutes standing-, consists chiefly of fine, red 

 sand, mixed with very little clay. The remainder is clay in a very 

 finely subdivided state, besides humus and some water of combi- 

 nation. The result of the mechanical examination thus shows that 



