4 per cent. of water retained by the hay, dried at
common temperatures, is driven off at 100 deg. 2,500 pounds weight
of hay, therefore, corresponds to 2,150 pounds, dried at 100 deg.
This shows us, that 984 pounds of carbon, and 32.2 pounds weight of
nitrogen, have been obtained in the produce of one morgen of meadow
land. Supposing that this nitrogen has been absorbed by the plants
in the form of ammonia, the atmosphere contains 39.1 pounds weight
of ammonia to every 3640 pounds weight of carbonic acid (=984
carbon, or 27 per cent.), or in other words, to every 1,000 pounds
weight of carbonic acid, 10.7 pounds of ammonia, that is to about
1/100,000, the weight of the air, or 1/60,000 of its volume.

For every 100 parts of carbonic acid absorbed by the surface of the
leaves, the plant receives from the atmosphere somewhat more than
one part of ammonia.

With every 1,000 pounds of carbon, we obtain--

From a meadow . 32 7/10 pounds of nitrogen.

From cultivated fields,

In Wheat . 21 1/2 " "
Oats . 22.3 " "
Rye . 15.2 " "
Potatoes . 34.1 " "
Beetroot . 39.1 " "
Clover . 44 " "
Peas . 62 " "

Boussingault obtained from his farm at Bechelbronn, in Alsace, in
five years, in the shape of potatoes, wheat, clover, turnips, and
oats, 8,383 of carbon, and 250.7 nitrogen. In the following five
years, as beetroot, wheat, clover, turnips, oats, and rye, 8,192 of
carbon, and 284.2 of nitrogen. In a further course of six years,
potatoes, wheat, clover, turnips, peas, and rye, 10,949 of carbon,
356.6 of nitrogen. In 16 years, 27,424 carbon, 858 1/2 nitrogen,
which gives for every 1,000 carbon, 31.3 nitrogen.

From these interesting and unquestionable facts, we may deduce some
conclusions of the highest importance in their application to
agriculture.

1. We observe that the relative proportions of carbon and nitrogen,
stand in a fixed relation to the surface of the leaves. Those
plants, in which all the nitrogen may be said to be concentrated in
the seeds, as the cerealia, contain on the whole less nitrogen than
the leguminous plants, peas, and clover.

2. The produce of nitrogen on a meadow which receives no
nitrogenised manure, is greater than that of a field of wheat which
has been manured.

3. The produce of nitrogen in clover and peas, which agriculturists
will acknowledge require no nitrogenised manure, is far greater than
that of a potato or turnip fiel