Farmyard Manure. 193 



manure, and, in short, that practical apparatus, without which 1 

 could not have entered on the investigation. During a period of 

 more than twelve months my leisure and that of my assistant, 

 Mr. Sibson (to whom I feel greatly indebted for his persevering 

 zeal and skill in this laborious task), has been almost constantly 

 occupied in studying the changes which farmyard manure under- 

 goes on keeping. 



It is not mv intention to write a paper on the best manage- 

 ment of farmyard manure, a subject on which considerable di- 

 versity of opinion prevails. I may do so, probably, at a future 

 occasion ; for the present I purpose simply to lay before the 

 reader the results of my practical and analytical experiments, and 

 to accompany them with some remarks, which I trust may help to 

 solve the question, how home-made dung ought to be prepared 

 and kept in the most profitable manner, so as to develop the full 

 efficacy of the excrements of our domestic animals, and the litter, 

 and to guard against loss in the fertilising constituents of dung ? 



In undertaking this investigation I encountered a difficulty, 

 which every one must have felt in experimenting on farmyard 

 manure, namely, the difficulty of obtaining a sample sufficiently 

 homogeneous to serve as the basis for future operations. In ex- 

 perimenting on fresh, or long dung, especially, it is no easy matter 

 to incorporate the long straw uniformly with the more minutely 

 divided droppings of animals ; perhaps altogether a perfect mix- 

 ture of both cannot be realised, and we must therefore be satis- 

 fied to make the mixture as intimate as the nature of the materials 

 will permit. I endeavoured to reach this point by employing 

 two men for the greater part of the day in turning a considerable 

 quantity of fresh long dung, composed of horse, cow, and pig 

 dung. By frequent turnings and distributions of the droppings 

 amongst the long straw I thus obtained a tolerably uniform 

 sample of mixed farmyard manure, which served as the basis for 

 all future experiments and analyses with fresh dung. In the same 

 way, l)ut more easily, a well-mixed samjile of well-rotten dung-, 

 composed of horse-dung, cows' and l)igs' manure, was obtained 

 a month later. This rotten dung, however, was not from the 

 same heap from which the fresh dung last mentioned was ob- 

 tained, but pr<)l)alj]y liad undergone fermentation for a period of 

 more than six months. It was wc;ll fermented, dark brown, 

 almost biac k spit-dung, taken from the; bottom of a corner of the 

 manure-pit, where the more perfectly decomposed manure is used 

 to be kept. 



In order not to encumber the description of my experiments, 

 and the statements of the results obtained in them, I shall give, 

 in an Appendix to this ])aper, a l)rii'f account of tlie methods made 

 use of in the performance of the following analyses. I may ob- 



voL. xvir. <• 



