Agricultural Ckemistnj. 
481 
to corn in the gross produce obtained will be much increased. 
It should be further added, too, as some qualification of the exact 
figures of the Table, that since the three seasons over which our 
average extends, include one at least which was unusually favour- 
able to the production of corn, the result by even the 400 lbs. 
of ammonia-salts, as here recorded, will be rather better than 
would be obtained over a more extended period of time. There 
was, however, a still further increase of produce when more 
ammonia was employed ; though, as already stated, the ratio 
of increase diminished the more rapidly the greater the excess 
of ammonia added in the manure. 
Upon the whole, then, the result strikingly stands out — tliat 
we obtained a considerably greater amount of produce by the 
use of much larger amounts of ammonia than those which Baron 
Liebig has pronounced to be excessive, and to the use of which 
he attributes the conclusion which he assumes to be so erroneous. 
It is further obvious that there was a very general uniformity 
in the proportion of increase obtained for a given amount of 
ammonia supplied, whether 400, 200, or 100 lbs. of its salts 
were added to the soil. ' Hence it follows, that if there were a 
loss of nitrogen when 400 lbs. of ammonia-salts were used, there 
must have been very nearly a proportionate amount of loss when 
the minimum quantity was employed ; and consequently that the 
loss observed when the 400 lbs. was used could not be due simply 
to the supply of more nitrogen than was necessary for a maximum 
of produce, as maintained by Baron Liebig. In fact, jt-e liave 
found the loss, and not made it ! 
Again, Baron Liebig says : — 
" The number 5, for the amount of ammonia, and tlie quantity 1 'bushel for 
the increased yield, are not expressions for a natural relation between manure 
and crops. The first does not express the weight of ammonia necessary to 
produce a maximum of increase, equal to one, and ascertained by a series of 
observations, but is a mere stroke of fancy." — Tliv Country Gentleman. 
We will first show, by quotation from our papers, whether 
we have assumed "the number 5 for the amount of ammonia, 
and the quantity 1 bushel for tlie increased yield," as an uncon- 
ditional and undeviating relation ; or whether these numbers are 
not given simply as a practical average of our experiments, ad- 
mitting deviations on eitlier side, according to variations of 
season and other circumstances. Secondly, we will show whether 
or not that which we have assumed, is " ascertained by a series of 
observations," or whether it is " a mere stroke of fancy." In 
regard to the first of these points, we say : — 
" I am inclined to think that, for practical purposes, we may assume 5 lbs. 
of ammonia to be required for the production of every bushel of wheat beyond 
