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MESSRS. J. B. LAWES AND J. H. GILBERT ON THE RESULTS OF 
character, of the produce of a crop under any circumstances so complex, it might be 
anticipated that there would be very great differences in its chemical composition, 
partly due directly to the supply of constituents by manure, partly to variation in the 
description of plants encouraged, and partly to the character and degree of develop¬ 
ment, and ripeness, of the varying components of the mixed herbage, according to the 
season and to the manure employed. 
With a view to the elucidation of this part of the subject, the dry matter and the 
ash have been determined in the produce of every plot in every season ; the nitrogen 
in that of all the plots for many of the seasons, and in some cases the amount of it 
existing as albuminoids has been determined. In selected cases, also, comparative 
determinations of “ crude woody fibre ” and of crude fatty matter have been made. 
About 120 complete ash-analyses have been executed. And, lastly, samples of the 
soil of every plot—in some cases at different periods, and in most cases representing 
the first, second, third, fourth, fifth, and sixth depths of nine inches, or, in all, to a 
total depth of 54 inches—have been collected, and these have been chemically examined 
in various ways. 
It is found that there is a considerable difference in the percentage of dry substance 
in the produce, and very considerable difference in the percentage of mineral matter 
(ash) in that dry substance. There is still greater difference in the percentage of 
nitrogen in the dry matter, and, again, a greater difference still in the percentage of 
individual constituents of the ash. When, indeed, it is remembered that a plot may 
have from 20 to 50 different species growing upon it, each with its own peculiar 
habit of growth, and consequent varying range and power of food-collection, it will 
not appear surprising that different species are developed according to the manure 
employed ; and, this being so, that the character and amount of the constituents 
taken up from the soil by such a mixed herbage should be found much more directly 
dependent on the supplies of them by manure than is the case with a crop of a single 
species growing separately. 
In further illustration it may be mentioned that, not only does the percentage of 
nitrogen in the dry substance of the produce of the different plots vary considerably, 
but the average annual amount of it assimilated over a given area is more than three 
times as much in some cases as in others. Again, the percentage of potass in the dry 
substance is three times as much in some cases as in others ; whilst the difference in 
the average annual amount of it taken up over a given area is more than five times as 
much on some plots as on others—dependent on the supplies of it by manure, and the 
consequent description of plants, and amount, and character, of growth induced. The 
percentage and acreage amounts of phosphoric acid also vary very strikingly; and so 
again it is with other mineral constituents, but in a less marked degree. 
The foregoing summary statements will be sufficient to indicate the general scope, 
objects, and results, of the inquiry. 
It will be seen that in the history of so many of what may be called natural rota- 
