AT DIFFERENT STAGES.

July 19. Aug. 2. Aug. 23. Aug. 30. Oct. 18.
Carbonic acid 5.40 2.850 0.65 3.50 4.050
Silicia 13.50 19.850 34.90 36.27 58.650
Sulphuric acid 2.16 1.995 4.92 5.84 4.881
Phosphates 21.60 16.250 17.00 13.50 5.850
Lime .69 4.035 2.00 3.88 4.510
Magnesia .37 2.980 1.59 2.30 0.865
Potash 9.98 11.675 10.85 9.15 7.333
Soda 34.39 29.580 21.23 22.13 8.520
Chlorine 4.55 6.020 3.06 1.63 2.664
Organic acids 5.50 2.400 3.38 2.05 2.200
----- ------ ------ ----- ------
98.14 97.750 98.187 99.83 99.334

The above figures disclose several interesting facts. It will be seen
that the increase of silica or flint in the leaf is steadily
progressive from 131/2 per cent. at July 19, to 58.65 at October 18.

Flint is substantially the _bone earth_ of all grasses. If one were
to analyse the bones of a calf when a day old, again when thirty days
of age, and when a year old, the increase of phosphate of lime in its
skeleton would be similar to that witnessed in the leaves and stems of
maize. In the early stages of the growth of corn, its leaves abound in
phosphates; but after the seeds begin to form, the phosphates leave
the tissues of the plant in other parts, and concentrate in and around
the germs in the seeds. On the 23rd of August, the ash of the whole
stalk contained 191/2 per cent. of phosphates; and on the 18th of
October, only 15.15 per cent. In forming the cobs of this plant,
considerable potash is drawn from the stalk, as it decreases from
35.54 per cent. August 16, to 24.69 October 18. When the plant is
growing fastest, its roots yield an ash which contains less than one
per cent. of lime; but after this development is nearly completed, the
roots retain, or perhaps regain from the plant above, over 41/2 per
cent. of this mineral. Soda figures as high as from 20 to 31 per cent.
in the ash obtained from corn roots. Ripe seeds gave the following
results on the analysis of their ash:--

Silica 0.850
Phosphoric acid 49.210
Lime 0.075
Magnesia 17.600