p.12

406

where it is deficient, and where grasses and grains are to be cultivated,
with profit and success.

The skillful microcopist is able to separate this coating of silica from
the other portions of the vegetable by means of heat, or of acids, and
thus exhibit "a perfect case of even the most minute vegetable structure
in flint. The paleae of Festuca pratensis exhibits a beautiful arrangement
of silica without any perparation."*

I have given the results of the chemical examination of all such species
as have been carefully analyzed, and to the results of which I have access.
These tables will be of great importance to the practical agriculturists
of our State by showing the necessity of keeping their soils always supplied
with such ingredients as these analysis show to be essential for the
growth and perfection of the plant. By their aid he can calculate with
considerable accuracy the amount of each element annually abstracted,
and consequently the amount that should be annually restored in the
shape of manures, or by other means. For these tables, it will be observed,
I am chiefly indebted ro [to] the Report of Professor E. Emmons on
the Agriculture of the State of New York, a work which not only does
honor to the author but to the State by whose liberal and enlightened
policy, the means necessary for the prosecution of the work were amply
provided. It only remains for our farmers to obtain correct analysis of
their soils to enable them to judge what crops are most suited to them;
and what deficiencies, if any, are to be supplied, to render them suitable
for the culture of any particular crop.

The proportion of grasses, as compared with the whole number of
species of flowering plants varies with the latitudes, elevation, degree of
moisture in the air, and other conditions affecting climate and the geographical
distribution of plants. In Wisconsin this proportion is about
one-thirteenth; and this is the fraction for Germany and France. ^1 In New
York ^2 and Vermont ^3 the proportion is a little greater, being one-twelfth.

In general the relative number of grasses diminishes as we approach
the equator; but this rule appears to be reversed on our sea coast, for at

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* Quickett, Practical Treatise on the Microscope, page 333.

^1 Humboldt, Views of Nature, p. 286.

^2 Torrey, Nat. Hist. N. York, Botany, vol. i., p. 7.

^3 Oakes, in Thompson's Vermont.