480 
Agricultural Chemistry. 
the crop in those cases xcas verii considerably increased ; though, as 
might be expected, in a diminishing numerical proportion to the 
excessive amount of ammonia now added. Then again, we have 
used, through the same series of years, respectively 200 lbs. and 
100 lbs. of ammonia-salts, with, in each case, a full supply of solu- 
ble phosphates and alkalies ; so that we have here again supplied 
the exact conditions demanded ; and also the means of determining- 
the "minimum" amount of ammonia which was effective in pro- 
ducing a maximum crop. Here, too, the results are precisely 
contrary to those which Baron Liebig has supposed they would 
be, and on the assumption of which lie says, that tlien " his con- 
clusions that the soil suffers a loss of ammonia would doubtless 
have been vastly modified. He has made the loss, and not found 
it." ! 
The following is a summary statement of the results obtained 
by the use of these gradationary amounts of ammonia, over a 
period in each case of three years, namely, 1852-4 inclusive. 
And in order to show by the side of these results, about what 
amount of produce was obtained on the same soil by means 
which the practical farmer will be better able to judge of, we also 
give the average produce by farm-yard manure during the same 
seasons ; and, by the comparison here afforded, it will be seen, 
that some of the supplied amounts of ammonia were very far in 
excess of what was required to give a produce equal to that by 
the annual supply of farm-yard manure. 
TAJ3LE VI.- 
-Showing the effects upon the Wheat Crop of graclationarj' amounts 
of Ammonia in IManure. 
Do. 
do. 
do. 
200 
Do. 
do. 
do. 
400 
Do. 
do. 
do. 
600 
Do. 
do. 
do. 
800 
Do. 
do. 
farmyard 
manure 
do. 
do. 
do. 
do. 
Total Increase 
per acre 
(Corn and Straw). 
lbs. 
760 
1,575 
2,915 
3,641 
4,555 
3,022 
Here it is seen that the 100 lbs., the 200 lbs., and the 400 lbs. 
of ammonia-salts, gave a gross increase of produce (corn and 
straw together), almost identically proportionate to the amount 
of ammonia in the manure. As we have already said, how- 
ever, the largest of these amounts (400 lbs.) is somewhat more 
than on the average of seasons will yield the most favourable 
result ; and if it be much exceeded, the proportion of straw 
