406 Report of Experiments with different Manures 
observed in the case of corn-crops grown under similar circum- 
stances. In illustration of the point in regard to the hay, it is seen 
that, whilst the average percentage of Mineral matter in the dry 
substanc e of the specimens grown without mineral manure was 
6'91, that, taking the average of the cases where artificial mineral 
manure was employed, was 8 01. It is true that, in those cases 
where mineral manure was employed with ammoniacal salts, the 
stemmy produce was somewhat less ripe, and hence, so far, the per- 
centage of Mineral matter in the dry substance would be expected 
to be comparatively high. On the other hand, the produce in 
these cases was almost entirely Graminaceous, and the Grami- 
naceous produce itself contained a large proportion of stem to 
leaf, and both of these circumstances would, other things being- 
equal, tend to a low percentage of Mineral matter in the dry sub- 
stance. In fact, upon the whole, the evidence is pretty clear, 
that the lower percentage of Mineral matter in the dry substance 
of the produce grown without mineral manure, was due to a rela- 
lative deficiency of available mineral constituents in the soil. The 
direct influence of the supply of mineral constituents by manure, 
upon the assimilation of them by this voracious crop, will be 
further illustrated presently, when speaking of the composition of 
the ash of the produce grown by the different manures. 
Where the mineral manures were used alone, more than ono- 
fifth of the produce consisted of Leguminous herbage. Hence, 
it might be supposed, that the percentage of Mineral matter in 
the gross produce, or hay, would be higher than where nitro- 
genous manures were also employed, and the produce was almost 
entirely Graminaceous. -Again, where the mineral was used 
without the nitrogenous manure, the proportion of the Grami- 
naceous produce that was leafy was much greater than where 
nitrogenous manures were also used. This circumstance, again, 
would tend to a high percentage of Mineral matter in the pro- 
duce grown by the mineral manures alone. But the fact was, 
that the percentage of Mineral matter in that produce was com- 
paratively low. The result was, doubtless, due to the fact, that 
a large proportion of this produce by mineral manure alone, 
v/as much riper than that grown by the mineral and nitrogenous 
manures combined. 
It appears then, that in the case of the complex and unripened 
produce — hay, the description of the herljage, t!ie character of 
development, the stage of progress at which the plants are cut, 
and the supplies within the reach of the growing crop, all have 
a marked influence upon the jiercentage of Mineral matter in tlie 
produce. The effects of different manure, in one and the same 
season, upon this percentage are, therefore, at least complicated, 
if not indirect. Nor do the relative percentages among a series ol 
