106 _THE CULTIVATOR. April, 
In some parts, Guano, which is rich in these matters, 
can be and is used, to supply phosphates. In England 
it is found advantageous to import bones, from a dis¬ 
tance, and to grind them to powder, to spread them on 
the soil. Which application increased the product, in 
some places, in two and even three fold proportion. 
In a country which consumes its own products where 
they are raised, and in which the animal excretions are 
not allowed to be washed away in the streams and riv¬ 
ers, the soil is kept fertile by the constant restoration 
to it of these mineral ingredients, in the bones and ex¬ 
cretions of animals which are applied to it. And poli¬ 
tical economists see in this fact, apart from other con¬ 
siderations, an immense advantage in a home consump¬ 
tion, bj home manufacturers;—in “placing the anvil 
by the side of the plow.” But when, as is the case in 
Kentucky at present, there is a constant exportation of 
vegetable and animal products, which are rich in the 
most valuable and indispensible ingredients of the soil, 
the fatness of the earth is steadily and certainly trans¬ 
ferred from the exporting to the importing country; and 
the land of the former will become poorer aud poorer, 
unless these valuable ingredients are, from some source, 
resupplied to it. 
Reflections of this kind caused me to turn my atten¬ 
tion to the rock stratum which underlies this fertile re¬ 
gion, with a hope of finding in it some compensation 
for this annual loss of the phosphates and the other es¬ 
sential elements of the soil. This rock is of the “Blue 
Limestone formation,” a lower member of the Silurian 
formation of the English geologists. It is the equiva¬ 
lent of the “Trenton Limestone” of the New-York 
geologists; and like that, is full of the fossil remains 
of marine animals:—the shells, crusts, coralloid struc¬ 
tures, of the ancient denizens of the primeval ocean, 
under which it was evidently deposited;—giving prom¬ 
ise, to the analyst, of the presence of all those ingre¬ 
dients which are essential to animal as well as to vege¬ 
table structures, and which have been already referred 
to as existing in all fertile soils. 
Our limestone presents various characters in its dif¬ 
ferent layers; some being hard, of a semi-crystalline 
structure, and of a bluish grey color; other specimens 
are more earthy in their composition, more shaley, of 
a darker color, falling readily to powder on exposure to 
the atmospheric agencies; all being in layers of great¬ 
er or less thickness, the solid masses being separated 
generally, by shaley matter. 
The hard gray rock is quite durable in its nature, 
and is extensively employed for turnpikes, for the foun¬ 
dation of houses, steps and walls; but all varieties change 
to a dirty buff color on the surface, in time, by the per¬ 
oxidation of iron; and disintegrate more or less rapidly, 
on exposure to the air: in consequence, doubtless, of the 
presence of protoxide and sulphuret of iron in the rock, 
which break up its structure when they unite with the 
oxygen of the air; as well as by reason of the presence 
of its numerous shells, and other fossil remains, which 
occasion minute fissures, into which water and air pe¬ 
netrate, and with the aid of frost, cause the rock final¬ 
ly to crumble. 
The hard layers burn into very good fat lime, which 
makes good mortar, but in consequence of the quantity 
of oxide of iron present in it, the-color is not as pure 
as is desirable for nice whitewashing. 
But few trials have been made of the fertilizing pow¬ 
ers of this limestone by our farmers, although it is so 
abundant and so easily to be obtained; no doubt because 
new land is cheap in the United States, and labor dear; 
more especially, because no immediate want of fertili¬ 
zers is felt by our agriculturists. But on the edges of 
our McAdamized roads, the corn rows which receive 
the powdered limestone in the form of dust, are obser¬ 
ved to be more flourishing than the others; and in pla¬ 
ces where the soil is very thin, and filled with frag¬ 
ments of the limestone, the product is always very 
good, when the season is not too dry. Gardeners, who 
have employed it on their small crops, speak highly of 
its utility as a fertilizer. 
It has been the custom in England and other coun¬ 
tries, as well as in some part of the United States, to 
use lime very freely on the arable land. It is, indeed, 
considered almost essential to the production of wheat; 
and enormous quantities of it are spread in some local¬ 
ities. A difference of opinion exists as to the manner 
in which the lime acts to improve the soil; for exam¬ 
ple, it is supposed that it aids the solution of hard ve¬ 
getable substances;—that it brings the silex of the soil 
to a soluble condition, and that it warms the earth and 
stimulates vegetation in some indefinable manner. But. 
it is probable, that if correct analyses were made of 
those limestones which are known to be the best ferti¬ 
lizers, another reason for its utility would be found in 
the presence in it of the essential mineral elements of - 
vegetables, viz: phosphates of lime and magnesia, sul¬ 
phate of lime, oxido of iron, potash, soda, &c. 
Chemical analyses of limestones and of soils, as they 
are ordinarily performed, are of but little practical va¬ 
lue even to scientific agriculturists, because they do not 
include the estimation of the phosphates and the alka¬ 
lies; which are the really essential ingredients, but 
which, in consequence of their existence in compara¬ 
tively small proportions, and because considerable labor 
and some skill are required to estimate them accurate¬ 
ly, are usually overlooked by the analyst. 
It would be far better, for agricultural purposes, to 
estimate only the phosphates and the alkalies, in a soil, 
a marl, or a limestone, than to give only the silex, the 
alumina, the oxide of iron, lime, and vegetable matter; 
which really are of less importance in this relation. 
During the past month or two, in my leisure mo¬ 
ments, I have submitted to analysis, several specimens 
of the Kentucky Blue limestone, and have been much 
gratified to find my anticipations realised in relation to 
its agricultural value, as will be seen by reference to 
the results given below. 
Specimen No. 1, is of the hard grey limestone; it 
was dug out of a well in the city of Lexington; it con¬ 
tains geodes lined with brown spar, pearl spar, cale 
spar and fluor spar and the usual fossils; its specific 
gravity is 2.45 in a dry specimen. On analysis, it was 
found to be composed of the following materials; viz: 
Carbonic acid,. 36.675 
Phosphoric acid,... 1.350 
Sulphuric acid, . 807 
Lime,. 47.046 
Magnesia,. 900 
Alumina and'oxide of iron,... 9 880 
Fine sand and silicates,. 1.790 
Moisture and loss,... 1.552 
100.000 
Specimen No. 2, from the hard thin layers which are 
more superficial than the first in this locality, yielded: 
Carbonic acid,. 40.53 
Phosphoric acid,... 36 
Sulphuric acid not estimated. 
Lime, .. 50.97 
Magnesia, .. 66 
Oxide of iron,. 32 
Alumina,. 15 
Sand and silicates,. . 6.52 
Moisture and loss. 49 
100.00 
In addition to these ingredients, potash and soda were 
obtained from the limestone, whenever the proper pro¬ 
cesses were employed; in one case as much as 0.0487 
per cent, of potash; in another, 0.0058 per cent. 
In two other specimens the proportion of sand, &c., 
was found to be as much as 13.5, and 20.3 per cent. 
As much variety, no doubt, exists in the composition, 
as in the appearance of the different layers of the lime¬ 
stone. 
