Clover as a Preparatory Crop for Wheat. 
407 
Composition of Soil, No, II. {Bad Clover), 
Water 17-24 
•Organic matter 9-64 
Oxides of iron and alumina 11-89 
Carbonate of lime 14-50 
IMagnesia, alkalies, &c 1-53 
Insoluble siliceous matter 45-20 
100-00 
2nd dctermiuation. 
* Containing nitrogen 'SOG .. -380 
Equal to ammonia •370 .. '470 
Both portions of the clover soil thus contained about the same 
percentage of organic matter, and yielded nearly the same amount 
of nitrogen. 
In addition, however, to the nitrogen in the clover-roots, a 
good deal of nitrogen, in the shape of root-fibres, decayed 
leaves, and similar organic matters, was disseminated througli- 
out the fine soil in which it occurred, and from which it could 
not be separated ; but unfortunately I neglected to weigh the soil 
from a square yard, and am, therefore, unable to state how much 
nitrogen per acre was present in the shape of small root-fibres 
and other organic matters. Approximately, the quantity might 
be obtained by calculation ; but, as the actual weight of culti- 
vated soils varies greatly, 1 abstain from making such a calcu- 
lation, even though it might be done with proprietv, as I took 
care in the following season to weigh the soil of different parts 
of the same field. 
Before mentioning the details of the experiments made in the 
next season, I will here give the composition of the ash of the 
partially cleaned clover-roots : — 
Composition of Ash of Clover-roots (j)artialli/ cleaned). 
Oxide of iron and alumina 11-73 
Lime 18-49 
Ma2;nesia 3-03 
Potash 6-88 
Soda 1-93 
Phosphoric acid S'61 
Sulphuric acid 2-24 
Soluble silica 19-01 
Insoluble siliceous matter 24'83 
Carbonic acid, chlorine^ and loss .. .. 8-25 
100-00 
This ash was obtained from clover-roots, which yielded, when 
perfectly dry, in round numbers, 8 per cent, of ash. Clover- 
roots washed quite clean, and separated from all soil, yield about 
5 per cent, of ash ; but it is extremely difficult to clean a large 
