Farmyard Manure. 71 



visable to put up a roof over the dung-pit. On the other hand, 

 on farms where there is deficiency of straw, so that the moisture 

 of the excrements of our domestic animals is barely absorbed by 

 the litter, the advantage of erecting a roof over the dung-pit will 

 be found very great. 



24. The worst method of making manure is to produce it by 

 animals kept in open yards, since a large proportion of valu- 

 able fertilizing matters is wasted in a short time ; and after a 

 lapse of twelve months at least two-thirds of the substance of the 

 manure is wasted, and only one-third, inferior in quality to an 

 equal weight of fresh dung, is left behind. 



25. The most rational plan of keeping manure in heaps ap- 

 pears to me that adopted by Mr. Lawrence of Cirencester, and 

 described by him at length in Morton's * Cyclopaedia of Agri- 

 culture,' under the head of c Manure.' 



APPENDIX. 



THE methods employed for determining the water, and selecting samples for 

 analysis, have been stated already in the preceding pages. I can, therefore, 

 proceed at once with the description of the other methods which were adopted 

 in the analysis of the manure. 



One thousand, and sometimes two thousand, grains of a carefully mixed 

 sample of manure were digested in a glass beaker with about 16 ounces of 

 cold distilled water for about three or four hours. The liquid was then 

 strained through calico, and the residue digested a second time with about 

 10 ounces of water ; the liquid was again passed through calico, and the 

 residue thoroughly squeezed out. It was next digested again in water, pressed 

 out, and repeatedly washed on the calico until the water came perfectly clear 

 through the calico, and left on evaporation merely a trace of solid matter. In 

 this way a quantity of liquid was obtained (by employing 1000 grains of 

 manure), which filled about a Winchester quart. As it was impossible to 

 obtain a perfectly clear liquid by repeated filtrations through fine filtering 

 paper, the watery solution of the dung was kept in carefully-stoppered Win- 

 chester quarts for three or four days, or until the liquid became perfectly clear 

 on standing. It was then drawn off with a syphon into another bottle, and 

 the deposit in the first bottle carefully collected in a weighed filter, and this 

 weight added afterwards to that of the portion of dung insoluble in water. 

 The insoluble portion was previously dried in the air-bath at 212 Fan. 



The weight of the whole solution having been ascertained, separate portions 

 of it were employed for the determination of the total amount of soluble 

 matters. Generally three, sometimes four, weighed portions of the liquid 

 were evaporated separately to dryness, first in glass beakers, and finally in a 

 large platinum basin over the water-bath. The platina basin and residue was 

 then dried in the air-bath, until it ceased to lose in weight. 



The dry residue of two evaporations was burned over the gas-lamp to a 

 whitish ash, and thus the amount of soluble organic and inorganic matters 

 determined. The dry residue of the third and fourth evaporation was reserved 

 for the determination of the nitrogen in the soluble matters of the manure. 



