Report of Experiments on the Growth of Wheat. 461 
In tlie 2nd year (1845), 10a and 10b were both manured with 
ammonia-salts at the rate of 330 lbs. per acre, and gave rather 
more than 31f bushels of dressed corn, and rather more than 
38 cwts. of straw, against scarcely 23J bushels of dressed corn, 
and only 24^ cwts. of straw, on plot 3 without manure. Thus, 
whilst a mixed mineral manure gave scarcely any increase what- 
ever in the first year, ammonia-salts alone gave an increase of 
rather more than 8J bushels of dressed corn, and about 13£ cwts. 
of straw, in the second. 
In the 3rd season (1845-0), ]0a being again manured with 
ammonia-salts, gave nearly 27 J bushels of - dressed corn, and 20 
cwts. of straw, against not quite 18 bushels of dressed corn, and 
13£ cwts. of straw, on the continuously unmanured plot (3). 
Ammonia-salts, again used alone, gave, therefore, an increase 
of nearly 9^ bushels of dressed corn, and about Gi cwts of straw. 
But plot 10b was left this year unmanured, and it gave about 
^ bushel less dressed corn, and £ cwt. less straw, than plot 3. 
Here, then, . neither the unexhausted residue of the mineral 
manure supplied in 1844, nor that of the ammonia-salts supplied 
in 1845, gave any increase in 1846. 
In the 4th year (1840-7), plots 10a and 10Z>, so differently treated 
in the preceding year, were again equally manured with am- 
monia-salts alone. The result was, almost identical amounts of 
both corn and straw in the two cases, and an increase over the 
unmanured plot of nearly 9 bushels of dressed corn, and about 
cwts. of straw. 
In the 5th year (1847-8), the two plots again received equal 
amounts of ammonia-salts, but 10b had in addition a mineral 
manure supplying potass, soda, magnesia, lime, sulphuric acid, 
and phosphoric acid. Plot 1 0b was, therefore, in a more favour- 
able condition than plot 10a, not only by virtue of this direct 
supply of mineral constituents, but also on account of the less 
exhaustion of them in 1840, when, being left unmanured, it gave 
so much less both of corn and straw than plot 10a. The result 
was, that, with 14f bushels of dressed com on the unmanured 
plot (3), 10a, with ammonia-salts alone for the 4th time, gave 
and 10b, with ammonia-salts for the 3rd time, and with 
mineral manure in addition, rather over 25 bushels ; and the 
amounts of straw were, on plot 3, 15^, on plot 10a rather more 
than 21, and on plot 10Z> rather more than 26 cwts. There was, 
therefore, an increase of 4i bushels of dressed corn, and 5f cwts. 
of straw, on plot 10a ; and of 10J bushels of dressed corn, and 
lOf cwts. of straw, on plot 10b ; or a difference in favour of 10/;, 
due to the greater abundance of mineral constituents, of nearly 
0 bushels of dressed corn, and of 5 cwts. of straw. There was, 
then, already in the 4th year of the application of the ammonia- 
VOL. XXV. 2 K 
