32 Farmyard Manure. 



Fully impressed with the force of such an argument, 1 was 

 anxious to determine, by direct experiments, the changes which 

 liquids like the drainings of dung-heaps and liquid manure 

 undergo when brought into contact with soils, and to ascertain 

 at the same time to what extent soils of known composition pos- 

 sessed the power of absorbing manuring matters from such com- 

 plex liquids. It is hardly necessary to observe that the results 

 to which the experiments to be described presently have led, 

 apply not merely to the liquids experimented with, but extend to 

 compound manuring matters in general and to farmyard manure 

 in particular, for the drainings of dung-heaps may, indeed, be 

 regarded as the very essence of dung. The deductions which can 

 be legitimately drawn from my experiments, therefore, apply in a 

 special manner to farmyard manure. 



In order to ascertain to what extent various soils possessed the 

 power of absorbing manuring constituents from the drainings of 

 dung-heaps, I determined to employ a limited quantity of soil 

 and a large excess of liquid. To this end, 2 parts by weight of 

 liquid were well mixed with 1 part by weight of soil, and left in 

 contact with the latter for 24 hours, after which the clear liquid 

 was drawn off and passed through a filter. 



EXPERIMENTS TO ASCERTAIN THE EXTENT OF ABSORBING 

 PROPERTIES OF SOILS OF KNOWN COMPOSITION. 



1. Experiment made with the Drainings of Dung-heaps com- 

 posed of rotten Dung. The drainings employed in this experi- 

 ment were the same which contained in the imperial gallon 

 664'64 grains of solid matters, the detailed composition of which 

 is given above. The composition of the soil used in the expe- 

 riment is given below. 



The surface-soil contained a good deal of organic matter, a 

 fair proportion of clay, little sand, and a moderate proportion of 

 carbonate of lime in the form of small fragments of limestone. 

 It was a stiffish soil, belonging to the clay-marls. Its subsoil 

 was richer in clay and of a more compact texture and less friable 

 character than the surface-soil. The mechanical analyses of soil 

 and subsoil gave the following results : 



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