406 
^here it is deficient, and where grasses and grains are to be cultivated 
with profit and success. 
The skillful microscopist 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 cast of even the most minute vegetable structure 
In flint. The paleae of Festuca pratensis exhibits a beautiful arrangement 
of silica without any preparation.”* 
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 sup¬ 
plied 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 ob¬ 
served, I am chiefly indebted ro 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 
-jpolicy, 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 geo¬ 
graphical distribution of plants. In Wisconsin this proportion is about 
one-thirteenth ; and this is the fraction for Germany and France.f In New 
York \ and Vermont j| 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 
* Quickett, Practical Treatise on the Microscope, page 333. 
f Humboldt Views of Nature, p. 286. 
t Toney, Nat. Hist. N. York, Botany, vol. i., p. 7. 
H Oakes, in Tkoupson’s Vermont. 
