26 SOILS AND MANURES. [CHAP. IL 



the valuable parts of the manure may be 

 washed away by the rain that falls on the heap 

 while the horse-dung is fermenting, a liquid 

 manure tank may be made to receive them. 

 Where practicable, it is, however, better to use 

 the remains of an old hotbed, or old celery 

 trenches or mushroom-beds, for manuring a 

 garden, than to procure, fresh dung ; as a great 

 deal of manure, and also of time and labour, 

 will be saved. 



It must be observed, that in using stable dung- 

 as a manure, there is one particular period in 

 the process of decay when the manure is more 

 efficacious than at any other; and this the 

 practice of gardeners has decided to be the 

 moment when the mass is sufficiently decayed 

 and amalgamated to be cut with a spade. Pro- 

 fessor Solly observes, that organic matters un- 

 dergo four distinct changes in their progress 

 towards decomposition: and these are fermen- 

 tation, putrefaction, decay, and mouldering ; 

 and it is when decay has begun, that stable 

 manure is in the most fitting: state for being; 

 applied to the soil. During the first process 

 (fermentation), stable manure is totally useless 

 as an agent of cultivation; and during; the second 

 process (putrefaction), it is principally used in 

 the form of hotbeds; but when the process 

 he calls decay has commenced, the elements 

 become separated from each other, so as to 

 form new compounds, till at last all the gaseous 

 products being dispersed, the residuum moulders 

 into dust. 



To facilitate the process of decay, it is abso- 

 lutely necessary that the manure should be ex- 



