ARTIFICIAL MANURES. 149 



fore, the farmer abstracts, perhaps, from this poor soil 

 the toilsome acquisitions of half a century, which 

 form the indispensable groundwork for a second and 

 more vigorous generation and for a progressive en- 

 richment of the ground. If he introduces a judicious 

 rotation of crops, and buys artificial manures for a 

 few years in addition, he will soon be in a position, 

 as many instances in Saxony have shown, to dis- 

 pense altogether with leaf-litter. And by this means 

 his wood, his field, and his purse will be in all re- 

 spects in a better situation.* 



VII. IMPORTANCE AND VALUE OF AR- 

 TIFICIAL MANURES. 



There are probably few farms on which natural 

 manure is produced in such plentiful quantity as to 

 suffice for perfecLly marmring their surface, and for 

 manuring so richly that no further increase of their 



* The leaves of the fir-tribe form, however, the most meagre kind 

 of leaf soil ; most of the other trees of the forest, when well decayed, 

 produce a carbonaceous substance of considerable value in the com- 

 post-heap as an absorbent and retainer of ammonia. And here 

 I would observe, that all carbonaceous substances of this nature 

 are extremely tenacious of moisture, and will retain a portion of it at a 

 heat even above that of boiling water. This character is, of course, 

 very valuable on light, sandy soils, and particularly during summer 

 droughts, and renders this substance of inestimable importance in the 

 compost-heap. — J. E. T. 



13* 



