REPORT ON TARIOrS MANURES AT CHISWICK. 
67 
under the same external conditions of supply in soil and atmo- 
sphere — indicatiDg, doubtless, not only very varyiDg ranges of 
root-collection, but also quantitatively varying functional cha- 
racters both of the feeders and the elaborating organs. 
A collective view of diagrams 1 to 6 shows, as a rule, but few 
marked differences in the relation of the amounts of growth of the 
various descriptions of plants compared one with another, under the 
six very varying conditions of soil-supply of constituents ; and, 
indeed, diagram 1, and column 1 in Table I., representing the 
growth without manure of any kind, shows in many cases but 
little or no less growth than that attained with some of the ma- 
nures — a fact sufficiently illustrative of the too high condition of 
the unmanured soil for the purposes of such experiments. But 
the effect of the different manures on each description of plant 
will be better studied by reference to diagrams 7-18. 
The twelve diagrams, 7-18, show, for each of the twelve 
descriptions of plants respectively, the comparative effects of 
the six different conditions of manuring. The continuous line, 
as in diagrams 1-6, represents the amount of dry produce in 
ounces; but the dotted line represents the proportion of mi- 
neral matter (ash) in tJie dry substance, each horizontal divi- 
sion indicating 1 per cent, of mineral matter in the dry sub- 
stance. 
"We will refer first to the effects of the different manures on 
each description of plant : — 
Diagram 7. Dactylis glomerata. — It will be observed that this 
very free-growing grass increases but little under the influence 
of purely mineral manures, but augments by about one half 
under the influence of each of the other manures, all of which 
supply a l^irge and equal amount of nitrogen, but in different 
states of combination or of association with other constituents. 
And here it may be well to observe that, preeminently so far 
as the grasses are concerned, the recognized characteristic 
effect of mineral manures is to favour elaboration or maturation 
rather than luxuriance ; whilst the characteristic effect of nitro- 
genous manures is to give luxuriance rather than maturing- 
tendency. The fact, therefore, of any increase by mineral ma- 
nures alone is some indication of the overrichness of the unma- 
nured soil in available nitrogen; and that, at the time of cutting, 
there was not more produce where the ammonia-salts or the 
nitrate was employed in admixture with mineral manures (the 
