USES OF VEGETABLE MOULD. 103 



powder, that it may again enter into the or- 

 ganism of plants ? The gardener who prizes his 

 well-rotted leaf soil for his floral nurslings, the 

 agriculturist who spreads his fields with steaming 

 loads of his farm-yard produce, and the majority 

 of persons unacquainted with the chemistry of 

 agriculture, will perhaps smile at our even ven- 

 turing to question the exceeding great value of 

 vegetable mould. When they behold the rich 

 blossoms and luxuriant stems of the conservatory, 

 and the soil groaning under a heavy harvest, 

 and all this fertility following the application 

 of vegetable manure, they appear to have a 

 natural and unquestionable argument in its 

 favour. Nor is its utility to be denied. The 

 question is On what does the fertilising property 

 depend ? 



One of the principal ingredients of plants is 

 the element carbon. Carbon is also the principal 

 ingredient of vegetable mould. Is the mould 

 then the true source of the carbon, or solid part 

 of vegetables? It was long thought to be so. 

 Liebig, with his usual happy method of demon- 

 stration, has now clearly proved that this long- 

 received opinion is an error. While we shall 

 return to this subject on a future occasion, when 

 it will be more appropriately introduced, we may 

 here mention that the fact is now well ascer- 

 tained, that pure vegetable mould is, when em- 



