Af/i icult a red Clicin idnj. 
483 
results obtained under eight different conditions as regards the 
nature of the nitrogenous manure, its amount, or the circum- 
stances under which it was employed, viz , whether with or without 
the addition of mineral manures. The number of cases brought 
under calculation, including both wheat and barley, amounts to 
nearly 300 ; and the number of years over which the experiments 
extended, was nine in the case of wheat, and three in tlie case of 
barley. The minor questions as to the influence of individual 
seasons, the varying proportions ot" corn and straw, the slightly 
varying percentage of nitrogen due to the combined influences 
of seas(m and manure, and other points, it would, of course, 
be impossible to treat of, in the mere outline which we are now 
professing to give. With regard, however, to the varying per- 
centage of nitrogen in the produce according to the amount of it 
in manure — a point to which Baron Liebig alludes — we may 
simply say, that it in no way materially affects the general result 
obtained. We may add, tliat the percentages of nitrogen in corn 
and straw respectively, employed in the calculations, are in most 
cases the results of direct determinations made upon mixed 
samples of the produce (grain and straw separately), of the 
several plots which go to form a single result in the Table. 
Table VII. 
Summarij — Nitrogen in total increase (Corn and Straw) for 100 in Manure. 
Chops — Wlieat and Bark'}'. 
General Description of JIannres. 
1. Ainmouia-salts (standard amount) alone 
2. Nitrate of soda ( do. do. ) alone 
3. Ammonia-salts ( do. do. ) with minerals . . 
. (■Ammonia-salts 1/ , , s , 
4. { , ■( do. do. ) do. 
( or rape-cake ) ^ ' 
5. Ammonia-salts (less than standard) do. 
6. Nitrate of soda ( do. do. ) alone 
7. Ammonia-salts (more than standard) with minerals 
g /Ammonia-salts K ^ 
( or rape-cake j ^ ■' 
Means .. 
Wheat. 
31-9 
29-3 
42-5 
38-3 
.'i3-4 
52-2 
39-9 
The results here stated may surely be considered as " ascer- 
tained by a series of observations." We have, first, the amount 
of nitrogen recovered in the increase of wheat and l)arley, when 
what is termed a " standard amount " of nitrogen alone, is em- 
ployed ; that is to say, such an amount as experience shows will 
yield a pretty full, but ratlier too heavy a crop to bear the 
