Farmyard Manure. 23 



a disagreeable odour ; and it is very likely that sulphite of mag- 

 nesia and sulphite of lime, on account of their great affinity for 

 oxygen, will prevent this evil by stopping the further decompo- 

 sition of animal matters deodorized by lime. Considered in a 

 purely sanitary point of view, M'Dougall's powder may there- 

 fore possess advantages over quick lime as a disinfectant. Still 

 it is difficult to conceive how such a farther decomposition can 

 be arrested practically by the use of this powder, for it appears 

 to me that this can only be realized by the employment of so 

 large a quantity of powder as to render the process altogether 

 too expensive. 



Drainings of Dung-heaps. Nobody can deny that farmyard 

 manure is seldom kept in the most efficient manner. In many 

 places in England, especially in Devonshire and in some parts 

 of Gloucestershire, it is a common practice to place manure- 

 heaps by the roadside, often on sloping ground, and to keep 

 these loosely-erected heaps for a considerable length of time 

 before carting the dung on the field. On other farms, the manure 

 is allowed to remain loosely scattered about in uncovered yards 

 for months before it is removed. Heavy showers of rain falling 

 on manure kept in such a manner, by washing out the soluble 

 fertilizing constituents of dung, necessarily greatly deteriorate its 

 value. It is well known that the more or less dark-coloured 

 liquids which flow from badly-kept dung-heaps in rainy weather 

 possess high fertilizing properties. According to the rain which 

 falls at the time of collecting these drainings, according to the 

 character of the manure, and similar modifying circumstances, 

 the composition of the drainings from dung-heaps is necessarily 

 subject to great variations. The general character of these liquids, 

 however, is the same in dilute and in concentrated drainings. 

 Several samples of dung-drainings were recently examined by me, 

 and, from their analyses, it will .be seen that they contain a 

 variety of fertilizing constituents which it is most desirable to 

 retain in dung-heaps. 



The first liquid examined was collected from a dung-heap 

 composed of well-rotten horse-dung, manure from fattening 

 beasts, and the dung from sheep-pens. Both the horse-dung and 

 dung from fattening beasts were made in boxes. The liquid 

 which ran from this dung-heap was collected in rainy weather, 

 and contained, no doubt, in addition to the liquid portion of the 

 dung, a good deal of rain. 



The colour of this liquid was dark brown; it contained no 

 free sulphuretted hydrogen, nor any free ammonia. Its reaction 

 was neutral to test-paper, but on boiling it became alkaline, 

 ammonia being given off freely. Besides ammonia, boiling 

 expelled a very considerable quantity of carbonic acid, which is 



D 2 



