Report of Experiments on the Growth of Wheat. 141 
ammonia-salts alone by 29^ bushels, with mineral manure alone 
by '.'I bushels; and with mineral manure and ammonia-salts 
together — with 100 lbs. of ammonia-salts by 17 bushels, with 
200 lbs. by 2H bushels, with 400 lbs. by 30 bushels, with 
600 lbs. by 32£ bushels, and with 800 lbs., by 30f bushels. The 
difference in quantity was, however, in reality much more than 
these figures indicate ; for whilst the weight of each bushel of 
dressed corn was in 18G3 from 62 to 63 lbs., in 1853 it in no 
case reached, and in some cases fell far short of, 52^- lbs. 
So far as the production of grain was concerned, therefore, the 
difference of result obtained in the two years was equally striking 
in point of both quantity and quality. 
The important practical question of the amount of ammonia in 
manure expended for the production of a given amount of increase 
in one season compared with another, according to the quantity 
employed, and to the available supply of mineral constituents 
within the soil, will be made a subject of separate consideration 
in the Fourth Section of this Report. 
The influence of each individual season, and of the extreme 
seasons, of the twenty, in tending to the development of much 
or little corn, much or little straw, and high or low quality of 
grain, under the different conditions of manuring, has now been 
briefly illustrated ; but before leaving the question of the influ- 
ence of season altogether, and passing to the more exclusive 
consideration of the effects of the different manures, it is desirable 
to endeavour to arrive at some conclusion as to whether the later 
or the earlier seasons were probably on the average the more 
favourable ; so that a proper judgment may be formed as to 
whether the actual results obtained by the use of any particular 
description of manure year after year on the same land, may be 
referred with but a little reservation to the manure employed, or 
whether they have been, in any material degree, influenced 
by a progressive or retrogressive character of the seasons of 
growth. 
There is an obvious inappropriateness in attempting to esti- 
mate the progressive or retrogressive productiveness of a series 
of seasons, by reference to the amounts of produce obtained on 
the application of a particular manure year after year on the same 
land, when the object of the estimate is to eliminate the influence 
of season from that due to the exhaustive or accumulative effect 
of the manure itself. 
The annual produce without manure would appear, at first 
sight, to be the best index of the relative character of the seasons. 
