Agricultural Chemistry. 
450 
judge for himself, whether on plot 22, the increased produce 
obtained was more probably due to free sulphuric acid, or to the 
still greater excess of phosphoric acid or its compounds supplied 
in the manure ; — that is to say, whether the increased produce on 
plot 22 was not due to an action very similar in kind to, but 
differing in degree from, that on plot 21 ? 
Again, Baron Liebig says, — 
"If we continue our examination, we shall find, still in his own experi- 
ments, much more convincing proofs that the excess of phosphoric acid 
cannot have been the cause of the increased iirodnce." — Principles, p. 12G. 
He then goes on to institute comparisons which, taking the 
figures simply as they stand, and without the explanations of the 
very results in question given in our papers, were certainly well 
calculated for his purpose, if the only object he had in view Avere 
to mystify, misrepresent, and fix contradiction upon agricultural 
phenomena. Thus, following up the incorrect assertion that " plios- 
phoric acid alone was found efficacious " in our experiments, by 
assuming that we should measure the action of farm-yard manure 
or rape-cake, by the quantity of phosphoric acid or phosphate of 
lime they contained, he goes on to compare the produce by these 
manures, sometimes in the same year, and sometimes not, with 
that by superphosphate of lime alone ; and then he says, in 
regard to these results, " in what incomprehensible contradiction 
do they stand to the opinions of Mr. Lawes ! " One quotation 
alone from our paper, to which, indeed, but for the length of this 
article, we had intended to add many more, will show not only 
whether we maintained that phosphoric acid alone icas efficacious, 
but whether or not it was to the phosphoric acid they contained, 
that we supposed the action of farm-yard manure and rape-cake 
Avas chiefly or only due.* Thus we say, speaking of superphos- 
phate of lime,-^ 
* As a further instance of the spirit and fah-ness of Baron Liebig's criticisms, he 
speaks of the " unpai-donable blunder " of using rape-cake as a carbonaceous ma- 
nure, — because, as he says, it contains a large amount of nitrogen also ; on which 
point he quotes the analyses of Mr. Way. Those who have not read our Papers, 
would scarcely think it possible, that we have again and again spoken in them of 
the amount of nitrogen in rape-cake ; and frequently also, particularly contrasted 
the effects of rape-cake and other organic manures, with that of ammonia-salts, in 
order to eliminate the action of the nitrogenous and carbonaceous supply respec- 
tively. But, Baron Liebig equally ridicules us, for using experimentally, rice and 
oil; substances chosen as containing little or no nitrogen. One of the carbona- 
ceous manures by which he obtained his results, was sawdust. His anxiety to 
ignore that we attribute an action to carbonaceous manures, and to ridicule all our 
experiments connected with such manures, is however perfectly intelligible, 
when it is borne in mind, that he claims to have embodied in his ' 14th Proposi- 
tion,' a correction and enlargement of his views. That Proposition is, he says, the 
only one of the 50 given in his ' Principles,' the substance of which is not to be 
found in his previous works ; and the object of that Proposition is to claim an 
action of animal and vegetable manures, by virtue of the organic substance they 
contain. We shall however have occasion to show, in one striking instance at 
