1374 MESSRS. J. B. LAWES, J. H. GILBERT, ANT) M. T. MASTERS, 
of nitrogen, was lower in the dry substance of the more gramineous and the riper 
produce of plot 14, than in the more mixed and less matured herbage of plot 16. 
Another point of interest brought out by a consideration of the mutual relations 
of the botanical and the chemical results is, that whilst with the heavier, the more 
simple, and the more gramineous herbage of plot 14, there was a greater actual 
quantity of both nitrogen and of mineral constituents taken up over a given area, 
the excess is comparatively small. In fact, with about 41 lbs. more nitrogen applied 
per acre per annum to plot 14 than to plot 16, the latter took up within about 7 lbs. 
per acre per annum as much as the former, and very nearly as much of several of 
the more important mineral constituents. The probable explanation of the obviously 
more complete utilization, either of the nitrogen supplied, or of the stores of it within 
the soil itself, is that, with the much greater variety of herbage, there was, at the same 
time, a more varied range of root-distribution,-and a more varied food-collecting 
capacity. And, with these, there was, with actually less of the mineral constituents 
taken up with equal supplies provided, still very much more in proportion to the 
nitrogen supplied, and to the increased luxuriance induced. 
12. Ammonia-salts (400 lbs. per acre), and superphosphate of lime) Plot 4-2. 
In the experiments hitherto considered in which nitrogenous and mineral manures 
were used together, the mineral manure has been very complex, supplying more of all 
the mineral constituents, excepting silica, than were taken up. The effects of a given 
amount of nitrogenous manure with more or less partial mineral manures will now 
be described; and from the results a judgment can be formed as to which of the 
mineral constituents the characteristic effects, botanical or otherwise, are to be attri¬ 
buted. Among the series the experiment first to be noticed is that in which the 
mineral manure consisted of superphosphate of lime alone; and the results obtained 
with this in conjunction with ammonia-salts (plot 4-2) will be compared, not only with 
those without manure, but with those with the same amount of ammonia-salts used 
alone, that is to say, without any mineral manure whatever (plot 5). The experiment 
with the superphosphate of lime and ammonia-salts (plot 4-2), like that with the 
superphosphate alone (plot 4-1), did not commence until the fourth year (1859). 
The addition of the superphosphate to the ammonia-salts increased the average 
amount of produce by more than one-third, the annual yield of nitrogen by about one- 
fifth, and that of the mineral matter taken up about in the proportion of from two to 
three. Not only was there very considerable increase in the amount taken up of those 
constituents which were supplied by the “superphosphate” (lime, some magnesia, 
phosphoric acid, and sulphuric acid), but there was also a considerably larger amount of 
both potass and silica, to say nothing of soda and chlorine, taken up, though neither 
of these was supplied. There is in these facts clear evidence of the defective supply 
of minerals on plot 5 compared with plot 4-2; but, inasmuch as the amounts of 
