SECT. VI. MANURES. 7Q 



as constituting a small proportion of vegetable food, Whether 

 they are not of themselves sufficient to support the n ' 

 plant, even with the assistance of water. Giobert 

 mixed together lime, alumine, silica, and magnesia, 

 in such proportions as are generally to be met with 

 in fertile soils, and moistened them with water. 

 Several different grains were then sown in this 

 artificial soil, which germinated indeed, but did not 

 thrive; and perished when the nourishment of the 

 cotyledons was exhausted. It is plain, therefore, 

 that the earths, though beneficial to the growth of 

 some vegetables, and perhaps necessary to the 

 health of others, are by no means capable of afford- 

 ing any considerable degree of nourishment to the 

 plant. 



SECTION VI. 



Manures. 



As the object of the preceding sections has been 

 that of exhibiting a brief view of the different species 

 of vegetable food, whether it be regarded as derived 

 from the soil or the atmosphere ; so the object of the 

 present section will be that of showing how the food 

 necessary to the support of the vegetating plant may 

 be supplied when defective, or restored when ex- 

 hausted : but this unavoidably involves the subject 

 of manures, or artificial preparations of vegetable 

 food, so important to the advancement of agriculture, 

 and consequent interest of mankind. 



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