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The extensive study which has been made in this laboratory
, of the insoluble silicates of our soils, during the past year, has
thrown much light on this subject, as well as on the probable
origin of some of our soils. All of the soils examined were
found to have a notable quantity of alkalies in the silicious
residue left after a ten, or twelve days' digestion in chlorohy-

dric acid of the density of i.i, and, as may be seen by refer-



ence to the table of extremes of composition given above,
this quantity varies from 2.640 per cent, of potash down to
0.399 per cent., which was the smallest proportion found in
any, and which, as is universally the case, is much greater
than the amount removed from the soil by the action of chlo-
rohydric or nitric acid.

The silicious residue of our Kentucky soils, left after pro-
longed digestion in the acids, is generally in such a fine state
of division that all or most of it will readily pass through fine
bolting-cloth. Hence our best Kentucky soil has been popu-
larly said to have no sand in it. Indeed, in the "Blue Grass
Region," so-called the most fertile part of the State sand is
so scarce that it usually must be hauled from the river beds at
some distance, and its cost to the builder is quite considerable.
But a large proportion of the very fine silicious residue of our
soils is really very fine quartzose sand, some grains being clear
and colorless, some milky or colored, and only a few, of the
same character, separable by the bolting-cloth from some of
the soils, are of a somewhat larger size, indicating the fact
that our soils, or the rocks from the disintegration of which
they are derived, have been deposited under comparatively
quiet waters, possibly of a deep sea at a distance from its

But, mixed with the purely silicious grains is quite a con-
siderable quantity of grains of silicates, containing the alkalies
in considerable proportions, doubtless of the nature of the
felspar and mica of the granitic rocks and other minerals
analogous in chemical composition, holding in reserve a great
treasure of these important elements of organic nourishment,
the alkalies.

When we consider the wide diffusion of these finely divided
silicates for it is probable they enter into the constitution of
all the soils of the world we may well be astonished at the
vast extent of rock disintegration which was necessary to their
production, and admire this wonderful provision for maintain-
ing the productiveness of the soil.



As regards the proportion of phosphates contained in these
insoluble silicates, it is the design of the writer to institute an
investigation, as occasion may favor, during the progress of
the Survey.

It has been conclusively established that mineral fertilizers
alone will not suffice to render soil productive. The greater
proportion of vegetable and animal bodies is made up of the
so-called atmospheric elements, viz: carbon, hydrogen, oxygen,
and nitrogen ; and the latter element, although entering into
their composition in much smaller proportions than the other
three, has most attracted the attention of vegetable physiolo-
gists and agriculturalists ; mainly for the reason, that while the
carbon is readily appropriated by the plant, in the decomposi-
tion of carbonic acid under the influence of the sun's light
this acid being never absent from the soil or the atmosphere
and water, always present, yields the necessary hydrogen and
oxygen, nitrogen cannot, as a general rule, with some excep-
tions, be directly assimilated from the atmospheric gases by
the .growing vegetable. With the exception of plants of the
clover or pea family, and a few others* all growing vegetables
must be supplied with this essential element, nitrogen, in some
form of compound, they not seeming generally to be endowed
with the force requisite to coerce into the liquid or solid state
this gas, which has withstood all the efforts of man, by the use
of immense pressure and intense cold, to condense it even
into the liquid form.

Under ordinary circumstances of natural vegetable growth,
nitrogen is presented to the plant, sometimes in the form of
ammonia (composed of nitrogen and hydrogen), or of some
of its compounds, resulting from the decomposition of animal
bodies and products ; sometimes in that of nitrates or analo-
gous compounds, which originate in the union of nitrogen and
oxygen and some base ; all of which nitrogenous compounds
are easily soluble in water, and thus readily enter the vege-
table tissues. But the ordinary natural supply of these com-
pounds is limited, and hence, when the soil is to be stimulated
to its highest degree of productiveness, and its fertility made

*Such as Indian corn. 1^


continuous, the cultivator necessarily resorts to the admix-
ture of nitrogenous compounds of some sort with his fertil-
izers. The nitrogenous organic compounds of both animals
and plants are always associated with phosphates ; and it is
believed, that while potash is absolutely necessary in the grow-
ing vegetable for the production and transfer of its non-nitro-
genous constituents, nitrogenous compounds and phosphates
are also mutually dependent all being equally indispensable.
So that the agricultural chemists of the Liebig school, who
contend for the exclusive importance of the mineral elements
of fertility, and those of the French and English schools, who
see no value in manures outside of the nitrogen compounds,
are equally too exclusive, and equally in fault.

These questions have long been of vital interest in the older
and more thickly populated countries, while in our compara-
tively new continent the virgin soil still bountifully responds
to the labor of the farmer without the aid of artificial fertil-
izers, and with but little evidence of exhaustion. But here,
as everywhere, except where the soil is continually renewed
by exceptional and local causes, such as the existence of an
unusually rich and readily decomposable sub-stratum, or the
periodical fertilizing overflow of rivers, the continued demands
of the farmer upon the land inevitably reduces its productive-
ness an effect which is increased as population enlarges.
And it is even now the fact that, over a large portion of our
State and country, profitable farming without the aid of ma-
nures is practically at an end. The future of our husbandry
will be mainly the application of fertilizers to the soil, as a
vehicle of production, by the aid of capital, skill, and indus-
try; which will be the more profitable as the population be-
comes more dense, and the home market is enlarged by the
increase amongst us of other industrial occupations, more
especially of the manufactures.

Kentucky is eminently endowed by nature for the support
of extensive and most important manufactures. Her im-
mense natural resources in coal, iron ores, clays, limestones,
salt, &c., &c. materials which are essential to almost all the


arts of civilization, and give employment to more individuals
than any other natural products, those of the field, perhaps, ex-
cepted only await development to make her one of the most
powerful Commonwealths of the world. The great wealth and
power of Great Britain rest on her coal and iron fields mainly.

During the past year, proximate analyses have been made,
in this laboratory, of one hundred and forty-seven several
samples of Kentiicky coals, in addition to those reported in
previous volumes of the reports. As might have been ex-
pected, these exhibit a considerable variety in their composi-
tion, as may be seen by examining the table at the end of this
chemical report.

The general average of ash and sulphur in the coals ex-
amined this year doubtless falls somewhat below that of the
samples examined in the previous year; but, as might be
expected, very great differences are to be observed among
them. Thus the limits of the ash per centage extend from
2.60 per cent., in Nos. 1908 and 1810, from Ohio county, to
34.72 per cent., in No. 1914, from Ohio county.

The great proportion of the ash of No. 1914 is exceptional,
however, and although this coal is called a cannel coal by
some, it doubtless should be denominated a bituminous shale.
Indeed, where the earthy matters exceed twenty per cent, of
the material, the name coal is not as appropriate as the latter
term, although the mineral may yet be made quite useful for
fuel, or possibly for distillation, in the vicinity of its bed.

The limits of total sulphur in these coals examined this
year are from 0.530 per cent., in the cannel coal, No. 1966,
from Wolfe county, to 7.959 per cent., in No. 1923, from Ohio

A remarkable fact in relation to this latter coal is, that while
the sulphur per centage is nearly eight the ash per centage is
only a little above twelve, indicating that much of this com-
bustible substance is either in the free state or in some form
of organic compound in the coal. Other coals, with a large
quantity of sulphur, show the same fact, and the inference is

that a considerable proportion of this sulphur maybe removed



in the operation of coking the coal. Remarks on the prob-
able condition of sulphur in coals, and on its removal, will be
found in the succeeding detailed report, especially under the
head of Bell county.

As was remarked in the previous volume, the coals of the
eastern coal field appear to be somewhat less sulphurous, in
the average, than those of the western. Recent imperfect
investigations into those parts of the eastern coal field which
are yet measurably unexplored, and which are beyond the
usual channels of communication, have shown the existence
there of coals of great value and remarkable purity, some of
which, like the celebrated Indiana '* Block coal," may be used
in the smelting of the abundant iron ore without the prelim-
inary process of coking.

Under the heads of Bell and Breathitt counties, the general
correspondence between the specific gravity and the ash per
centage was again exhibited ; and it is to be noted, that while
the density of the coal, as a general rule, increases with the
ash per centage, the cannel coals offer a marked exception, or
exhibit a ratio of their own. What the ratio is, in the differ-
ent sorts of coal, cannot well be made out at present, espe-
cially because the different varieties shade into each other,
and difference of age and the action of physical agencies may
affect the relative density, independent of the earthy matters,
as well as the various kinds of organic materials from which
the coals were derived.

To illustrate more fully this correspondence between specific
gravity and ash per centage, another table, viz: that of the
coals from Ohio county, is appended, as follows:



Specific grav-

Ash per cent-


Specific grav-

Ash per cent-
























































' -3'o













4-3 6










* A bituminous shale or impure cannel coal.

It is believed, that notwithstanding the large proportions of
ash and sulphur in some of these samples of coals analyzed,
the generator average quality of the coals of the very exten-
sive coal fields of Kentucky will compare favorably with that
of the coals of any other region.

Only about twenty-four iron ores, of the limonite variety,
and five clay iron-stones have been analyzed since the last
report. These are from seven counties only, and are found
to vary in their proportions of iron between the extremes of
twenty-three and more than fifty-three per cent of that metal.
Their proportions of phosphorus vary from 1.60 to 0.065 P er
cent., the largest proportion of this injurious element having
been found in the "Clinton ore," of Old Slate Furnace, of
Bath county.

As is pretty well established, phosphorus is more injurious
to the quality of the iron than any other ingredient of the
ore, especially in causing it to be "cold-short," or, in other
words, diminishing its tenacity or toughness. Silicon, in cer-
tain proportions, is also injurious in this respect ; but the
presence of phosphorus in the ore is more to be deprecated,
because it is to be removed with more difficulty from the
iron in the subsequent refining processes; silicon being easily
oxidated, or burnt out with the excess of carbon and some
other impurities of the pig metal, in the puddling or even in



the Bessemer process, while phosphorus is believed to main-
tain more obstinately its union with the metallic iron.

The general belief was, even among modern scientific ob-
servers, that all the phosphoric acid in the iron ore, or in the
flux material and fuel, used in the ordinary smelting furnace,
finds its way into the reduced metal, pig iron, produced, and
is held in it, in firm combination, in the form of iron phos-
phide. Hence, it was claimed, a phosphatic ore necessarily pro-
duces a yet more phosphatic iron, because the phosphorus, all
of which is supposed to combine with the metal, is, of course,
in larger proportion to the iron than to the ore, &c.

But analyses, made by the writer, of samples of iron furnace
cinder or slag, published in the volumes of the first series of
reports of the Kentucky Geological Survey, as well as in the
present report (see Greenup county), show the presence of
notable quantities of phosphoric acid in this slag, and thus
lead to the conclusion that it is possible, by a proper manage-
ment of the furnace and of the fluxes used, to eliminate, in
this form, a considerable proportion of this injurious ingredient
in the smelting of the ore. If the phosphatic iron ore, in the
high furnace, be subjected to a very intense heat, in presence
of the reducing gases, the phosphoric acid will be reduced to
phosphorus, which will unite with the reduced iron when it
melts, provided a proper basic flux material be not present to
fuse with the phosphoric acid before it is deoxidated, and thus
protect it from reduction. But, in the presence of such a basic
flux material, it is probable that the iron of the ore, if it be
reduced at a more moderate heat, and while yet unmelted,
may afterwards melt at a heat not quite high enough to
reduce the phosphoric acid, which then would go off in the

The strong affinity which exists between alumina and phos-
phoric acid justifies the belief that this material, in the flux
or in the ore, may be especially useful in this process of
purification in the smelting furnace ; when used in combination
with a sufficiency of lime or other fluxing materials to make a
rather fusible basic flux, and with not too high a temperature


in the reducing part of the furnace. It is well known that
alumina is an essential ingredient of all clays.

It has long been known that the phosphorus of the impure
iron may be removed, in great measure, by the aid of oxygen
and fluxing materials ; and this fact has long been practically
applied in the various refining processes, in which the melted
pig metal is exposed to the oxygen of the air, or to that which is
separated from powdered iron or manganese oxides, or derived
from common nitre or nitrate of soda. The oxygen burns out
or oxidates the phosphorus (together with the other oxidable
ingredients carbon, silicon, sulphur, &c.), and the phosphoric
acid which is formed unites generally with iron or manganese
oxides, as phosphates, in the melted cinder. This is the the-
ory of all the various refining processes, including that called
puddling and the Bessemer process, which latter process, how-
ever, because, probably, of the want of a fluid basic flux to
dissolve compounds of phosphoric acid, is not effectual in the
removal of phosphorus.

Amongst the modern processes for iron purification is the
patent one of Henderson, originated in England, but which
seems to have been employed in this country, at the Hamburg
Iron Works, Hamburg, Pennsylvania. An English pamphlet,
obtained by the writer at the Centennial Exhibition, gives
many interesting facts in relation to it and its results. The
refining process is, to pour the melted impure pig metal on a
mixture of powdered fluor-spar and titanic iron ore (ilmen-
ite), or peroxide of manganese, &c., placed on the floor of
the ordinary puddling furnace; "the furnace door being then
closed, the powdered mixture fuses, and the iron is allowed to
boil for about half an hour; the rabble is then worked for
about ten minutes, and the metal is balled up in the usual
.way. The whole time occupied by one charge, with ordinary
grey forge pig iron, being a little under an hour."

It is claimed, that in this time the commonest and most im-
pure pig iron may have most of its phosphorus, sulphur, sili-
con, and carbon removed; and that it may be brought to a
state of purity, toughness, and ductility equal to that of the



best Swedish iron. In this pamphlet this claim is corrobo-
rated by numerous chemical analyses of the pig metal and of
the purified wrought iron, by Dr. Henry M. Noad, F. R. S. ;
Mr. Edward Riley, F. C. S. ; and Mr. W. Matthiew Williams,
F. C. S., as well as by many mechanical tests of the metal by
Mr. David Kirkaldy.

The chemical analysis of the slag produced in this pro-
cess throws a little light upon the theory of the depurative
action of the re-agents used. (See table 19 of the pam-
phlet.) Some of this slag, analyzed by Mr. Edward Riley,
F. C. S., gave the following results:

Silica II. 12

Titanic acid ... 5.02

Protoxide of iron "56.41 1 r .

Peroxide of iron 18.20}= &' per cent, of ,.

Alumina . ." 1.73

Manganese 2.22

Phosphoric acid 1.19 .47 per cent, of phosphorus.

Sulphur .09

Lime 3.51


The author of the process asserts that most of the phos-
phorus goes off in the form of vapor; but it is evident that
it mostly separates in the slag, after having formed phosphoric
acid by union with oxygen. No doubt the manganese oxide
aided in the oxidation of the carbon, sulphur, and phosphorus
of the pig iron, and the fluorine of the fluor-spar may have
combined with the silicon to produce a volatile fluoride of sil-
icon ; for we see no statement of any fluorine in the analysis
of the slag; but -it is believed, that in the ordinary operation
of puddling, the atmospheric oxygen, or that derived from a
lining of powdered iron ore, &c., may remove all these, if it
be carefully performed, more especially if materials be brought
in contact with the boiling iron, which may readily melt into a
sufficient basic cinder to carry off the fixed impurities, including
phosphates which may result from the oxidation of the phos-
phorus of the iron. That the fluor-spar may both serve to
form the flux and quicken the separation of the silicon and
phosphorus, was fully established by Carron.


A large quantity of iron oxides appears in this cinder, in
the above statement of the analysis, equivalent to fifty-eight
per cent, of the whole slag. But it is probable that most of
this was derived from the powdered ilmenite (titanic iron
oxide) used in the process. In the ordinary puddling slag
the large proportion of iron oxide always present is derived
from the pig iron. It is very probable that the mixture of the
powdered iron ore with the fluor-spar may lessen the loss of
metal in the puddling. According to the published state-
ment, the loss in purifying the most common pig iron into
fine wrought iron, by the Henderson process, is only ten per

It is generally believed that, in the ordinary refining pro-
cesses, the agent which is especially effectual in the removal
of the phosphorus is the tri-basic silicate of iron, which forms
a fluid cinder or slag, and which is produced by the oxidation
of the ingredients of the pig metal at a great expense of
iron. There can be no doubt that this loss may be measur-
ably prevented, and the purification facilitated, by the use of
a "lining" of powdered oxide of iron (iron ore), with some
compound of lime (fluor-spar or limestone), to give oxygen
and form a fluid basic flux to carry off the phosphoric and
silicic acids, &c. Whether the use of similar materials, to
furnish oxygen and the ingredients for a somewhat basic flux to
carry off phosphoric acid, is possible in the Bessemer process,
is well worthy of trial. Fluor-spar commends itself because of
its ready fusibility and its power of fluxing earthy materials
generally, so that it possibly may dissolve, retain, and pro-
tect from reduction the oxidated phosphatic compounds, at a
temperature sufficient to melt iron, and thus aid in their re-
moval. The presence of alumina in the cinder seems also to
be beneficial in this respect.

Not the least interesting of the iron ores analyzed, during
the past year, are those described in the Appendix as Clinton
iron ore, dyestone ore, or fossil ore, from very extensive beds
in the mountainous region of Tennessee, near the Kentucky
State line, in the Cumberland Gap region, which, because of



their abundance in the vicinity of our coal beds, their general
richness in iron (one sample giving more than fifty-six per
cent, of this metal, on analysis), as well as because of their
unexpected moderate proportion of phosphorus, in this local-
ity, promise to become of great industrial value.

Some of the iron smelted from this Clinton ore, at the Old
Clinton Furnace, at Cumberland Gap, the analysis of which is
also given in the Appendix, corroborates this expectation.

The twenty-two samples of pig iron analyzed, from five
counties of the State, vary in their specific gravity from 6.163
to 7.435 ; in their per centage of iron, from 89.687 to 94.764;
in their per centage of total carbon, from 2.800 to 4.720; in
that of phosphorus, from 1.080 to 0.120; in that of silicon,
from 5.082 to 0.363, and in that of sulphur, from 0.278 to
o.on. This includes samples of hot-blast stone-coal iron, as
well as cold-blast charcoal iron. From these and the analyses
previously made, it is evident that iron of almost any desir-
able quality can be manufactured in our State from her natural
products, which are unusually abundant, and await only the
judicious application of capital, skill, and labor to give to her
great prominence as a manufacturing State.

An interesting discovery of a phosphatic layer in the blue lime-
stone (Lower Silurian) is recorded under the head of Fayette
county; and some suggestions as to the use of the Bittern
water of our salt works, and other means in rendering more
available for fertilizers the beds of marls of our State, will be
found tinder the heads of Clay and Grayson counties.

Another interesting fact reported is the existence of barium
and strontium chlorides in the brines of Clay and Meade coun-


Limonite iron ores, labeled as follows :
No. 1652 LIMONITE, from Slate Furnace ore banks, "Howard's

Hill;" Upper Silurian formation. Collected by P. N. Moore.

In porous, or fine cellular, irregular, thin laminse ; oolitic in
parts; of a dark-brown color, with ochreous incrusting mate-


No. 1653 LIMONITE, from Slate Furnace ore bank. Upper

part of the bed. Collected by P. N. Moore.

Mostly of a yellowish-brown color, and somewhat friable,
with some darker-brown and denser irregular laminae. The
whole presenting a fine-grained oolitic appearance, from the
presence of small spherical cavities, more or less incrusted
with whitish and yellowish material.

No. 1654 LIMONITE ORE at the Chalybeate Springs, Pilot

Knob. Collected by P. N. Moore.

In thin irregular laminae, of a dark reddish-brown color,
with some bright red and yellowish ochreous material.

No. 1655 LIMONITE (with carbonate), said to be eighteen to
tiventy feet thick, from near Owingsville , on the road to
Slate Creek. Collected by P. N. Moore.

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