1360 
MESSRS. J. B. LAWES, J. H. GILBERT, AND M. T. MASTERS, 
There was even still more total produce, and still more nitrogen and mineral matter 
taken up, with the addition of the silicates ; and, over the later as compared with the 
earlier period, the falling off in the yield of hay and its contents of mineral matter 
was less, and the increase in the assimilation of nitrogen was greater, than in the case 
of 11-1. There was, nevertheless, with an actual diminution in the amount of mineral 
matter, and an increase of that of nitrogen, taken up in the later years, evidence of a 
relative deficiency of available mineral matter compared with the available nitrogen. 
Under the influence of the silicates, there was an increase in the amount of the mineral 
constituents in the produce far beyond that of the increased quantity of silica taken 
up, which was extremely small in proportion to that supplied. Indeed, besides the 
increased amount of silica, lime, and soda, taken up, these being supplied, there was 
also more magnesia, potass, phosphoric acid, sulphuric acid, and chlorine, gathered; 
though none of these were supplied in greater amount than on 11-1. We have, 
therefore, with the same supplies of nitrogen, and of all the mineral constituents, 
except silica, lime, and soda, which were in increased amount, nevertheless a greater 
activity of accumulation, and greater than could be due to the direct supply of con¬ 
stituents by the silicates used. It is probable that the alkaline silicates reacted within 
the soil, serving to neutralise sulphuric acid and chlorine, and to liberate nitrogen and 
mineral constituents in an available condition ; and also that, with the increased growth, 
the plants acquired increased root-range, and increased capacity of food-collection. 
Referring to the table of botanical results, it will be seen that there were on the 
average rather fewer species on 11-2 with, than on 11-1 without the silicates, the 
average number found in the samples being only 18. There was also a somewhat 
higher average percentage of grasses in the produce ; the proportion being more than 
99 in the third, and nearly 97 on the average of the four separation-years. There was 
absolutely no leguminous plant found in any of the samples. This was so, notwith¬ 
standing that there was supplied as much potass as, and more of some other mineral 
constituents than, on plot 7, where the Leguminosse were so prominent; there being 
there no nitrogenous manure in addition to give the Graminese such pre-eminent 
advantage in the struggle. Among Miscellanese only two, Rumex Acetosa and Cono- 
podium denudatum, contributed as much as 1 per cent, to the produce in any one 
separation-year, and of these the Rumex has gone down to only about 1 per cent., 
and the Conopodium to a mere fraction in the later years; all other miscellaneous 
species collectively not yielding, on the average, a quarter of 1 per cent. 
The chief point of interest in the detail of the botanical results is the difference of 
effect as compared with plot 11-1 without the silicates. There is seen to be in the 
later separation-years a very great increase in the relative amount of Alopecurus 
pratensis, a great increase also in that of Avena elatior, and some in Poa pratensis 
and Holcus lanatus ; whilst Agrostis vulgaris, Dactylis glomerata, and most other 
grasses yielded, in the later years, less than on 11-1. 
Thus, with the addition of silicates of lime and soda, we have more nitrogen, and 
