licport of Experiments on the Growtii of Barletj, 
Table I. — Average Quantity and Quality of Barley per Acre, per annum, on selected 
plots. Twenty Years, 18r)2-1871. 
Plots. 
4 A 
4 A A 
4 C 
'AVERAGE PllODUCE, &c., PER ACRE PER ANNUM. 
MANURES, PER ACRE, PER ANNUM. 
Dressed Com. 
Unmauured 
14 Tons Farmyard Manure . 
Mixed Mineral IMamn-e, alone 
200 lbs. Ammonia-salts, alone 
("Mixed Mineral Manure, and 
\200 lbs. Ammonia-salts .. 
I Mixed Mineral Manure, and . . 
400 lbs. Ammonia-salts first G years 
200 lbs. Ammonia-salts next 10 years 
275 lbs. Nitrate Soda last 4 years 
{Mixed Mineral Manure, and.. 
2000 lbs. Eape-cake first 6 years 
1000 lbs. Rape-cake last 14 years.. 
j Weight 
Quantity. per 
I Bushel. 
Bushels. 
20 
48i 
4G1 
493 
lbs. 
.'52 -3 
54-3 
53- 4 
52-1 
54- 0 
53-4 
472 
Total 
Corn. 
lbs. 
1133 
27(:8 
1550 
1840 
2630 
2813 
2G98 
„. Total 
btraw Produce 
Cbaff. Vtraw). 
Cwts. 
Hi 
28| 
14i 
18i 
28| 
323 
29J 
lbs. 
2454 
5933 
3162 
3919 
5817 
C443 
6002 
Cora 
to 
100 
Straw. 
86-6 
88- 5 
96-4 
89- 2 
83-2 
79-5 
83-0 
alone ; but only about 14 bushels more coi-n, and 10 cwts. more 
straw, than the ammonla-salts alone. 
There can be no doubt, therefore, that in this, in an agri- 
cultural sense, already corn-exhausted soil, the available supply of 
nitrogen was much more readily exhausted than the available 
supply of mineral constituents, so far as the requirements for the 
growth of barley are concerned. 
It may be stated at the outset then, that the results obtained 
with barley, so far show general accordance with those on wheat; 
and that those with both crops are entirely inconsistent with 
the " Mineral Theory," according to which it was maintained — 
" that the supply of ammonia is unnecessary for most of our 
cultivated plants, and that it may be even superfluous, if only 
the soil contain a sufficient supply of the mineral food of plants, 
when the ammonia required for their development will be fur- 
nished by the atmosphere." 
We need hardly say that the sharp distinction, the direct 
antithesis, between the terms " mineral " and " ammonia," as 
used in the above sentence, was habitually adopted by Baron 
Liebig in his earlier agricultural writings*; in fact, the " Mineral 
Theory" which was so long in controversy, can hardly be more 
clearly stated in so few words, than in those just given, written 
by himself. 
* For a few additional illustrations see foot-note pp. 506-8, vol. xxiv. part 2 of 
this Journal. 
