Agricultural Chemistry. 
477 
salts in the soil, whatever might he its exact vahie, must have increased from 
year to year, because amnioniacal salts (sulphate of ammonia and sal-ammoniac) 
are not volatile, and, consequently, the uuconsumed ijortiwi, or excess, must have 
remained in the soil. TJiis heing assnmcd as a fact ichich cannot he disputed, 
these numbers establish the truth, already demonstrated by the earlier cxjieri- 
ments, that the proiluce did not increase in proportion to the increased projmr- 
tion of nitrogen present in the soil ; but that, with the exception of the year 
1848, the produce for the same amount of nitrogen steadily diminished." — 
Principles, p. 97. 
It is after the wholesale i<inoring of our recorded facts, state- 
ments, and conclusions, which these quotations imply, and after 
such reasoning upon the pure assumptions taken in their stead 
as we have pointed out aljove, that Baron Liebig, using the word 
proportio)ial " in tlie exact numerical sense (which he well knows 
is entirely inconsistent with all our evidence and reasonings 
on this question), sums up his criticism by saying : — 
" Mr. Lawes has disproved ivhat he intended to prove, namely, tiiat the 
excess of produce in this case is proportional to the quantity of ammonia 
present in the soil ; — that is, he has jiroved that a single, donlle, or treble supply 
of ammonia docs not give a single, double, or treble excess of produce ; but that 
this excess is a constant quantity." — Principles, p. 135. 
Already, however, in Germany, America, and this country, 
Baron Liebig's treatment of this question has been prominently 
commented upon. And thus it is, that he has been obliged to 
recur to the facts and conclusions involved in this part of the 
subject. At the recent meeting of the British Association at 
Glasgow he undertook to deal with this question ; and as the 
line of argument he tiien adopted was substantially that which 
he had already published in Germany in reply to the admirable 
strictures on his 'Principles' by Professor Wolff,* we shall, for 
convenience, refer to the translation of his own reply, made and 
published at his own (Baron Liebig's) request in America.! 
In discussing this question, we need not for a moment enter- 
tain as an objection against observed collateral facts, Baron 
Liebig's argument, that if there be a loss of nitrogen in the 
growth of inci-eased produce, there must necessarily be the same 
relation between the normal supplies of nitrogen and the amount 
assimilated under their influence on our unmanured plot. It 
must then be distinctly borne in mind, that it is of actually 
observed facts, in relation not to the growth of produce alone, but 
of an increased amount of produce by means of an accumulation 
of nitrogen within the soil, that we have now more particularly to 
speak. We may, however, say in passing, that we have frequently 
called attention to facts regarding the amount of constituents 
harvested over a given area of unmanured or equally manured 
* Zeitschrift fur Deutsche Landwirthe, 4en Heft. 
t The Country Gentleman. Albany, N. Y., October 11, 1855, et scq. 
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