10 The History of a Meld newly laid down to Permanent Oi'asS. 
soil and treatment, wten the meadow may be said to be formed, 
it is found that the soil contains very much more vegetable 
matter — amounting, in fact, to many thousands of pounds per 
acre in the first 9 inches of depth. Thus, in the case of some 
of the experimental plots of the old grass-land at Eothamsted, 
samples have been taken to the depth of 9 inches, the whole of 
the above-ground growth having been first carefully cut off by 
scissors, and the vegetable matter remaining in the soil picked 
out by hand. The average of twenty-four such determinations 
indicated 16,601 lbs. (nearly 7^ tons) of vegetable matter per 
acre; and in one case the amount was 24,548 lbs., or nearly 11 
tons per acre. The nitrogen in this residue amounted, on the 
average of the 24 samples, to about 125 lbs. per acre, and in the 
case of the maximum amount of residue, to about 180 lbs. 
Again, the nitrogen in the first 9 inches of the soil of the 
barley-land above referred to, after the roots had been separated, 
amounted to 0'1416 per cent, in the fine dry soil, the average 
weight of which was about 2,600,000 lbs. per acre to the same 
depth ; so that the amount of nitrogen in it would correspond 
to about 3,682 lbs. per acre. The nitrogen in the fine dry soil of 
the clover-land was 0'1566 per cent., which, reckoned on the same 
weight of surface-soil, corresponds to 4,072 lbs. per acre to the 
depth of 9 inches. On the other hand, the surface-soil of the old 
grass-land, which yielded the amounts of roots above referred to, 
indicated, for the average of the 24 samples, 0-2346 per cent, of 
nitrogen ; but the weight of fine dry soil — that is, excluding stones, 
roots, and water — amounted to an average of only about 2,000,000 
lbs. per acre to the depth of 9 inches. Hence the amount of 
nitrogen to that depth would be about 4,692 lbs., or much more 
than in the case of the clover-land, and very much more than 
in that of the barley-land, though with much less soil. The 
highest amount of nitrogen found in the surface-soil of any 
of the experimental grass plots was, however, 0"2737 per cent., 
corresponding to 5,474 lbs. of nitrogen per acre on a weight of 
2,000,000 lbs. 
With the increase of nitrogen, as the arable land is converted 
into meadow, there is also a considerable increase of carbon. 
Thus, in the surface-soil of the experimental grass-plots at 
Rothamsted, there are about 13 or 14 parts of carbon to 1 of 
nitrogen ; whereas, in the case of the Eothamsted arable surface- 
soils, there are only from 10 to 11 parts of carbon to 1 of nitro- 
gen, and in the subsoils much less. The relation of carbon to 
nitrogen in the surface-soil is, however, very much less than in 
the vegetation above it, and very much less than in the roots 
separated from it. Both the nitrogen and the carbon of the 
