ON THE FOOD OF PLANTS. 14-7 



*< with a pump, by which any fluid matter may 

 " be collected for the use of the land. It too 

 " often happens that a dense mucilaginous and 

 " extractive fluid is suffered to drain away from 

 " the dunghill, so as to be entirely lost to the 

 ** farm.'* 



My previous objections to the application of 

 Sir Humphry's ideas, must be equally strong 

 against the mode here recommended. 



Those who are in the habit of making hot- 

 beds for vegetables, know that fresh dung from 

 the stable, packed together without a sufficient 

 degree of moisture, to modify its fermentation ; 

 will very speedily acquire a high degree of 

 heat, and throw oft' a quantity of elastic vapour ; 

 either carburetted hydrogene, or ammonia, and 

 that as the moisture declines, the heat will also : 

 and the dung will then be overrun with moul- 

 diness, or fungii, and thus during such ferment- 

 ation, the exclusion of moisture or rain, by 

 a shed being placed over it, must facilitate and 

 increase the loss by such evaporation, and by the 

 evolution of the gases j and the earth covering 

 dung in this state, will not afterwards support 

 vegetation. As the chief supply of manure is 

 derived from the stable and farm yard, the ar- 

 rangement and management of these is a matter 

 of no trivial iiTi))ortance. 



L -2 



