136 Farmyard Manure. 



4. By allowing the washings of dung-heaps to run to waste^ 

 not only ammonia is lost, but also much soluble organic matter^ 

 salts of potash and other inorganic substances, which enter into 

 the composition of our crops, and which are necessary to their 

 growth. 



II. Drainings from another Dung-heap. 



These drainings were not so dark-coloured as the preceding 

 ones. Like the former liquid, it was neutral, but gave off 

 ammonia on boiling and on addition of quick lime. 



Hydrochloric acid produced a dark-brown coloured flaky 

 deposit, leaving the liquid only pale yellow. 



The amount of the precipitated humus acids was much smaller 

 than in the preceding liquid. 



For want of a sufficient quantity of liquid, only the amount 

 of solid matter contained in it could be determined. 



An imperial gallon on evaporation furnished 353"36 grains of 

 solid matter, dried at 212° Falir. 



III. Drainings from a third Dung-lieap. 



A dung-heap, composed chiefly of mixed fresh horse, cow's or 

 pig's dung, furnished the material for the third analysis of drainings. 



This liquid was much darker than the two preceding liquids, 

 possessed an offensive smell, although it contained no sulphu- 

 retted hydrogen. Itwas neutral to test-paper, consequently did 

 not contain any free or carbonate of ammonia. On heating, am- 

 monia escaped, apparently, however, in much smaller c[uantities 

 than from the preceding drainings. 



This liquid was collected at a time when no rain had fallen 

 for several weeks, which circumstance accounts for its greater 

 concentration. It was submitted to the same course of analysis 

 as the first drainings. 



7000 grs. evaporated to dryness produced 135'774 grs. of dry 

 matters; and. this quantity, on burning in a platinum dish, fur- 

 nished G2"58 grs. of mineral matters. A separate portion was 

 used for the determination of the amount of ammonia present in 

 the form of salts ; and another portion of liquid, acidulated with 

 a little hydrochloric acid evaporated to dryness, was employed' 

 for the determination of the whole amount of nitrogen. 



By deducting the amount of nitrogen found in the ammoniacal 

 salts from the total amount of nitrogen obtained by combustion 

 of the solid matter with soda-lime, the proportion of nitrogen 

 contained in the organic substances of these drainings was 

 ascertained. 



The following Table represents the composition of the solid 



