4 Liquid Manure. 



The first filtration experiment was made with a soil from field 

 No. 19 of the Royal Agricultural College Farm, Cirencester. 



Submitted to a mechanical analysis, this soil was found to 

 contain, in 100 parts, 



Moisture 1-51 



Organic matter ll'OB 



Carbonate of lime 10'82 



Clay 52-06 



Band 24'53 



100-00 



It appears from this that the soil in question is a calcareous 

 clay. In wet weather it is very sticky and stiff; worked in dry 

 weather it breaks up in hard unmanageable lumps. By autumn 

 cultivation its physical properties have been considerably im- 

 proved. A portion of the soil, taken from a large well-prepared 

 sample, yielded, on being submitted to chemical analysis, the 

 following results : 



Moisture 1*51 



Organic matter and water of combination . . 11 '08 



Oxides of iron and alumina 14- 25 



Carbonate of lime 10'82 



Sulphate of lime 



Magnesia 



Potash (in acid solution) 



Soda (in acid solution) 



Phosphoric acid 



Insoluble silicates and sand (chiefly clay) 



101-13 



This soil was mixed with liquid manure in the proportion of 

 2000 grains of soil to 7000 grains of perfectly clear liquid 

 manure, the composition of which has just been stated. After 

 shaking the soil and liquid together, and repeating this at in- 

 tervals several times, the whole was allowed to settle ; after a lapse 

 of 24 hours the tolerably clear liquid was syphoned off. Notwith- 

 standing that the filtration through fine filtering-paper was re- 

 peated many times, the liquid remained somewhat turbid. It 

 was found, however, that a perfectly clear liquid could be ob- 

 tained by allowing the filtered liquid to subside for eight days, 

 and then carefully pouring off the clear liquid from the small 

 deposit. This course has been followed in all subsequent ex- 

 periments, and yielded tolerably satisfactory results. 



The liquid manure originally had a brown colour ; after filtra- 

 tion through the soil the colour of the liquid was scarcely less deep. 



A portion of the clear liquid was evaporated to dryness, and in 

 the residue the amount of fixed ammonia and nitrogen deter- 

 mined by combustion with soda-lime. 



