198 HANDY-BOOK OP HUSBANDET. 



formed, and gypsum is developed, and these fix the ammonia as 

 fast as it is generated. 



14. " During the fermentation of dung, the phosphate of lime 

 which it contains is much more soluble than in fresh manure." 



15. Ammonia is given off in the heated interior of the fer- 

 menting heap, but it is arrested by the organic acids and the gyp- 

 sum in the colder external layers. 



16. While ammonia is not given off from the surface of well- 

 compressed heaps, it is v/asted in appreciable quantities, when 

 they are turned over. 



17. " No advantage appears to result from carrying on the fer- 

 " mentation of dung too far, but every disadvantage." 



18. "Farm-yard manure becomes deteriorated in value when 

 '* kept in heaps exposed to the weather — the more the longer it is 

 "kept." 



19. The loss from manure-heaps kept exposed to the weather 

 is not so much due to the evaporation of ammonia as to the wash- 

 ing out, by rains, of the soluble ammoniacal salts and other solu- 

 ble fertilizing parts. 



20. " If rain is excluded from dung-heaps, or little rain falls at 

 *' a time, the loss in ammonia is trifling, and no saline matters, of 

 ** course, are removed ; but if much rain falls, especially if it 

 *' descends in heavy showers upon the dung-heap, a serious loss in 

 *' ammonia, soluble organic matters, phosphate of lime, and salts 

 *' of potash is incurred, and the manure becomes rapidly deterio- 

 ** rated in value, while, at the same time, it is diminished in weight." 



21. "Well-rotten dung is more readily affected by the deteri- 

 *' orating influence of rain than fresh manure." 



22. " Practically speaking, all the essentially valuable manuring 

 ** constituents are preserved by keeping farm-yard manure under 

 *' cover." 



23. If there is a very large amount of litter in the dung, 

 water must be added to it, by pumping or by rain, to enable it 



.to ferment actively. 



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

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



