Ar/riciiUu ra I Chcm istry . 
499 
mont, but that there vere no ostahllshed principles to _2:uicle its 
advance, nor even any sure jjround on which to tread if any 
deviation were made either to the right or to tlie left of the beaten 
track marked out by our forefathers. 
The appearance of Baron Liebig's book was, therefore, natu- 
rally and deservedly hailed with gi'eat delight. All admired the 
masterly way in which he traced the elements of vegetable life 
to their original sources, pointed out their chemical composition, 
and followed them through the various stages of the plant's deve- 
lopment and maturity, until the process of decay had again 
reduced them to the elementary form. His main position too, 
that in order permanently to maintain the fertility of cultivated 
land, it was necessary to restore to it all the substances contained 
in the various crops exported from the farm, was as new to agri- 
culturists as it Avas convincing, and its application to practical 
agriculture seemed as simple and easy as it has since been found 
to be complicated and difficult. 
For the time, however, tlie whole secrets of the science of agri- 
culture seemed to be laid open by the production of this master- 
key ; nor could it well be otherwise. The accuracy of the 
chemical investigations which formed the basis of this work 
has never been questioned, and the reasoning with which the 
various results were united into one consistent and comprehen- 
sive scheme, seemed so sound and satisfactory, that the de- 
liglited reader was led on by easy steps until he reached an 
elevation from which it was difficult to avoid believing that the 
prospect before him included the whole past, present, and future 
of agriculture. 
But however perfect the theory in the case of normal vegeta- 
tion, such as that of our natural woods and plains, or when 
applied to the reclamation of a virgin gravel-pit, it was soon found 
that the teaching of Baron Liebig's work, though invaluable in 
its suggestive capacity, was yet not sufficiently matured to be of 
use to the practical agriculturist; and the entire failure of the 
numerous special or xiniversal manures which appeared in rapid 
succession, not even excepting the one which received the sanc- 
tion of the great philosopher himself, plainly proved that his 
•various conclusions required important modifications before they 
could be made applicable to the artificial wants of improved 
agriculture. These modifications have been supplied by Baron 
Liebig from time to time in his later works, after personally in- 
specting the existing condition of practical agriculture in Great 
Britain. Suggestions of a totally opposite kind have been advo- 
cated by Mr. Lawes ; and it is on the comparative merits of 
• these respective adjustments that British agriculturists are now 
.called on to decide. 
