Farmyard Manure. 147 



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 

 combination. The result of the mechanical examination thus 

 shows that the proximate constituents of this soil are present in 

 an advanced state of decomposition. In the following tabular 

 statement the minute chemical composition of the same soil is 

 given : — 



2. Chemical Analysis. 



Moisture 3-45 



* Or2;anic matter and water of comLinatiou .. 13'94 



Carbonate of lime '"^^ I ^eTher^-^o^o*"' ' 



Sulphate of lime "^3 i fi^e!' 



(Containing S O3 '31) 



Alumina 14-74 



Oxide of iron 5-87 



Magnesia "18 



Potash (in a state of silicate) .. .. '25 



Chloride of sodium '11 



Phosphoric acid, combined with iron and alu- ■> ,^.->. 



miua (equal to bone-earth •131) / 



Soluble silica (soluble in dilute potash) . . . . 7'42 



Insoluble siliceous matters (almost entirely 1 ,..■,. 09 



white sand) j- ou <j_i 



100-181 



* Containing nitrogen •192 



Equal to ammonia -228 



5000 grains of this soil were mixed Avith 5000 grains of liquid 

 from fresh manure heap, and 5000 grains of distilled water. 

 After twenty-four hours the clear liquid was filtered from the 

 soil, and found to be somewhat lighter-coloured than before ; but, 

 in comparison with the decolourising properties of the clay-soil 

 used in the experiment with the drainings from rotten dung, its 

 effect upon the dark-coloured organic compounds in the liquid 

 appeared to be weak. 



A portion of the filtered liquid was used for the determination 

 of the ammonia contained in it in the form of volatile salts, or, 

 at any rate, in the form of salts which yield ammonia on boiling 

 their watery solution. Another portion was evaporated to 

 dryness, and the amount of nitrogen in the dry residue deter- 

 mined. The rest of the liquid was used for the determination 

 of solid matter and ash. 



Leaving unnoticed the details of these various determinations, 

 I shall state at once the composition of the drainings passed 

 through this light sandy soil. 1 may observe, however, that the 



l2 



