Agricultural Chemistry. 
425 
wbicli, from various circumstances, a rational agriculture, without a supply 
of manure in some shape or other /rcwi. without, seems nearly impossible." — 
lb., p. 24. 
Now, on what principles, and by what constituents, does 
Baron Liebig propose to provide England with a manure '■'■from 
witliout," equal in its composition and effects to genuine guano, 
and to the solid and fluid excrements of animals and men ? He 
goes on in the same page to say, " The following salts may be 
regarded as the essential constituents of a powerful manure ap- 
plicable to all descriptions of soil." He then enumerates under 
this head, all the constituents indicated by analysis in animal 
manures, including, not only the mineral constituents, but am- 
monia, decaying vegetable matter, &c. But, immediately after- 
wards, speaking of the mineral substances, he says : — 
" These are the substances which together give fertility to the soil ; but 
although each of them may, under certain circumstances, — namely, where 
the soil is defective, or where it is not indift'erent to the plant to take up one 
instead of the other, as, for instance, may be the case with soda instead of 
potass, — increase the fertility, no one of them can be regarded as manure, 
according to the common meaning of the word, for the simple reason, that 
only all of them, in certain proportions, will fulfil the purpose for which the 
common manure is applied. This purpose is the restoi-ation, or an increase 
of the original fertility, and by manure we must replace all the constituents oj 
the plants which have heen taken away in the harvest, or which are contained 
in the plants which we are desirous to cidtivate.'' — lb., p. 26. 
Having thus stated the principle upon which a manure jf?'0??z 
without, and to replace guano and the solid and fluid excrements 
of animals and men, should be compounded, he says: — 
"What, then, are the constituents of the soil which we remove by the 
straw, seeds, tuberculous roots, stalks, &c., of our plants of culture ? It is 
obvious that we must know these first, in order to restore them in sufficient 
quantities. To this we answer, by giving the analysis of the ashes of plants 
and their seeds." ! ! 
After this overwhelming amount of evidence on the point — 
culminating as it does to an almost exact reflection of what we 
have assumed in our Papers to be the Mineral Theory of Baron 
Liebig as applied to agriculture — after all this evidence from 
his own writings, we need scarcely ask : — 
Is there in the sentence of our Paper, of which Baron Liebig^ 
so much complains — is there, we ask, in that sentence, that of 
which he should say : — 
In it — " I find two erroneous statements, the continued dif- 
fusion of which I can no longer tolerate " ? 
Or is he justified in asserting that he has never said — " That 
the produce of land is proportional to the supply or diminution 
of the available mineral constituents " ? 
That — " I find in my work only one passage in which I speak 
of the land of England in the sense understood by Mr. Lawes " ? 
