ON MANURES. 



41 



not only a large quantity of fluid, but likewise of gaseous mat- 

 ter, is lost ; so much so, that the dung is reduced one-halti and 

 from that two-thirds or more, in weight. Now, the principal 

 elastic matter disengaged is carbonic acid, with some ammo- 

 nia; and both these, if attracted by the moisture in a soil, and 

 retained in combination with it, are capable of becoming nutri- 

 ment' Reasoning on which, he says — ' that, within the last 

 seven years, Mr. Coke has entirely given up the system of 

 applying fermented dung ; and he informs me, that his crops 

 - have been as good as ever they were, and that his manure 

 goes nearly twice as far.' He then sums up his arguments 

 with directions for the management of putrescent manure, in 

 the following terms : — 



' Where farm-yard dung cannot be immediately applied, the 

 destructive fermentation of it should be prevented as much as 

 possible. For this end the dung should be kept dry and un- 

 exposed to the air; for the moisture and contact with the 

 oxygen of the atmosphere tends to excite fermentation. To 

 protect a heap from rain, a covering of compact marl, or of a 

 tenacious clay, should be spread over the surface and sides of it. 

 Watering dung-hills is sometimes recommended for checking 

 fermentation ; but this practice, although it may cool the dung 

 for a short time, is inconsistent with just views*, for moisture is 

 a principal agent in all processes of decomposition: dry fibrous 

 matter will never ferment. Water is as necessary as air to 

 the process, and to supply it to fermenting dung is to supply 

 an agent which will hasten its decay.' 'If a thermometer 

 plunged into the dung does not rise above 100° of Fahrenheit, 

 there is little danger of much aeriform matter flying off; if 

 the temperature is higher, the dung should be immediately 

 spread abroad.' 



There is no ground for contesting the fact that a large 

 quantity of fluid and of gaseous vapour is allowed to escape 

 during the common process of reducing farm-yard manure to 

 the state of short muck ; but the practical inference deduced 

 therefrom can only be proved by experiments on a much 

 broader scale than those which have been yet submitted to 

 the public. 



The separation of a rich fluid substance, drained from a 

 mass of dung, must, doubtless, diminish the fertilizing power 

 of the manure in the proportion in which it has been ex- 

 tracted ; but these drainings can either be preserved in tanks, 

 and afterwards either thrown over the heap or applied to the 



