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Some of our iron masters and proprietors of furnaces have heen more punctual, and I embrace this opportunity to tender my sincere thanks to them for the valuable information which they have communicated to me respecting their works, and for the specimens which they have sent me for examination.
With the exception of the Cranberry ore in Carter county and a vein in Cocke county, both belonging to the magnetic oxide of iron, and the red iron ore, a vein of which I have traced with some interruption for about sixty miles on the eastern base of the Cumberland mountains, the iron ore in other counties of Tennessee all belong to the hydroxide: of iron, and if their product differs in quantity or in quality it is only attributable to some heterogeneous substance which is combined or mixed with the iron in the ore, or to the ignorance of those who work it.
I had in contemplation for sometime to give a complete description and analysis of the various ores which are found in the State of Tennessee, particularly of those which are used in our iron works, because, though these ores belong to the well known hydroxides of iron, all the different varieties of that mineral are not well known to those who have the direction of these useful establishments. When I first visited , our iion works I was surprised to see some of the best varieties of ore rejected as useless. The brown hæmatite, the purest and richest of all, was by some rejected under the name of Black Jack. Now the ore to which the English miners give the name of Black Jack, is not an iron ore, but a compound of zinc and sulphur. The iron masters were astonished when I pronounced it the best ore they had.
I have also promised in former reports to furnish a complete statistical account of these works, in preparing which I expected the cooperation of the proprietors of these works, but only a few have contributed to this undertaking. The facts nevertheless, which have come to my knowledge, I will now communicate, and I again invite those who have not yet done it, to send me such information as they çonsider fit for the eye of the public, that it may be seen what benefit they are to the State, and to what extent legislative patronage should be bestowed upon works, which furnish or may furnish one of the most essential sources of support to the State.
I will commence with the ore of the Dover iron works. They are situated on the left side of Cumberland river, a few miles above Dover, in Stewart county, and are composed of two high furnaces and a rolling mill, and are owned by Messrs. Woods, Stacker & Co.
The ore banks of this establishment are of great extent and are all situated in the immediate vicinity of the furnaces. One only of them furnishes at present the ore which is used. It is the bank called Bear Spring bank; it forms a solid deposite of ore and is quarried above ground, as is the case with all the iron banks in Tennessee. I have made analyses of the ores from the other banks belonging to that establishment; they are not used now, for what reason I do not know, for they are as rich in metal as those of Bear Spring bank. The average result of several analyses made of different parcels of the ore is:
Protoxide of iron,
70 00--614 per cent. of pure iron. Waier,
12 00 Manganese,
2 50 Silex,
4 50 Alumine,
1 00 Loss,
1 00 The ore of these banks is a mixture of some of the varieties of the hydroxide of iron, namely of the compact brown iron stone, forming the greatest proportion, which is here and there interspersed with cavities and porous places, containing some of the earthly varities as the yellow and brown iron ocher; the interior of the cavities being often lined with brown hæmatite which also runs sometimes through the massive ore.
The ore of Bear Spring bank which is now exclusively used in the Dover works, is more homogeneous.. When I visited these works, this bank was not sufficiently penetrated to enable me to form an opinion respecting the nature of the ore in general, but judging from the specimens which the proprietors sent me, it is principally composed of compact brown iron stone in stalactitical concretions, containing numerous cavities which are mostly lined with a black crust-in one instance a crystal of sulphate of lime, of about two inches in length, in an almost isolated state was found in it.
A small vein of earthly black oxide of manganese intermixed with yellow ocher traverses this bank in several directions.
I have made two analyses of the compact variety—the one an ore of rather a pale brown or liver color-it gave: Protoxide of iron,
SO=62 per cent. pure iron. Water,
100 The second being performed with a blackish, somewhat glossy ore, gave: Protoxide of iron,
76,50=595 per cent. pure iron. Water,
100,00 The earthy variety is a mixture of yellow and brown ocher with parcels of pulverulent black oxide of manganese and silex, one anaylsis gave me fifty-four per hundred of protoxide or forty-two per hundred of pure iron.
From a statement communicated to me by the proprietors of the
above mentioned works, it appears that they manufacture annually about 5575 tons of iron, viz:
2000 tons of bar iron,
550 tons of blooms. To produce this quantity they purchase annually about 1600 tons of blooms, the remainder being furnished by their two furnaces.
The establishment owns 235 slaves, and hire nearly the same num. ber giving direct employment at the mill and two furnaces to about 450 hands, and feeds and supports about 100 women and children.
If we add to these 450 effective hands the number of hands which are employed indirectly by the establishment, the number will be about one thousand, viz:
In making the above mentioned 1600 tons of blooms from the ore,
360 In digging and transporting stone coal,
80 I raising corn, flour, pork, etc.
Add the hands immediately employed in the establishment,
990 They employ 200 head of mules and horses and thirty-five yoke of
Consume annually, 300,000 pounds pork, 7,000 barrels corn,
300 barrels flour, 100,000 bushels stone coal,
44,000 cords wood, The annual expenditure of money is $240,000.
The sales of wrought iron, nails, castings and pig metal of that establishment for five years, commencing 21 October 1834, and ending 20 October 1839, is $1,950,000.
Though Mr. E. Embree has made no communication for the contemplated statistical account of the iron works of this State, the information communicated by him is in other respects of the highest importance, as giving the results of the experiments of a man who is perfectly master of the iron business, and show that stone coal is not absolutely necessary to carry on the rolling of iron, as is generally believed, so that in the several counties in East Tennessee, which are too remote from our coal fields, and which possess in great abundance excellent iron ore, the iron business in all its ramifications can be conducted to any extent; rendering thereby available the great extent of mountain land, which is only calculated for the growth of timber.
Vir. E's, works are situated on Bumper's creek, near Volychucky riv, er in Washington county. Ile stated to me that he had been engaged in making iron for nearly thirty years in a country where no stone coal can be got, and that he had found the following results from the use of wood.
"'i'o keep a smelting furnace in constant operation making about twenty tons of metal per week, requires from 7,000 to 10,000 acres of common mountain land, such as is found uncultivated along the Unaka and Smoky mountains, this amount of land will reproduce the wood so as to keep up a constant supply.
Chestnut will yield a good cutting in about fifteen years.
Oak is of a slower growth, it will require twenty-tive years to produce as large a quantity as is generally lound at the first cutting.
Black oak or chestnut oak will make about twenty per hundred more iron than chestnut. * Pine is of slower growth than chestnut and will make a little more iron to the cord.
Spruce and white pine are not good for coal but answer for heating blooms.
I have met with no timber except linn (lime?) and buckeye, but what will answer to make iron; but the wood that makes the heaviest coal will make the most iron, to the volume of it.
: I believe the chestnut oak, found in the mountains, is a little superior to any other wood, because it makes the heavest coal. It is also superior to any other wood in heating blooms for rolling—though any kind of wood in the mountains will answer for heating blooms except the two kinds before mentioned.
I use wood for heatiug blooms for rolling, and find it answers very well. It requires from two and a half to four cords to heat a ton of blooms suihiciently to roll it into sound bar iron.
A litte pine or poplar, well dried, and mixed with good black or chestnut oak, makes the best heat.
The time mentioned above to produce the wood, is sufficient for the growth of a crop equal in quantity to the first; the ground inay be cut over in a shorter time, but there would be a loss in the quality as well as in the quantity.
In Kentucky, where the land is well timbered, five thousand acres are considered sufficient to produce wood to make 1000 tons of pig iron annually."
The above mentioned facts, the results of thirty years experience, of a close and intelligent observer as Mr. Embrée, have induced me to lay before the inhabitants of our forest and iron regions a more extensive view of the nature of wood as fuel for the use of iron works.
In order to give an idea of the quantity of heat produced by the va. rious kinds of our wood, I have made some extracts of a memoir of Mr. Bull, of Philadelphia, entitled “Experiments to determine the compar.
ative value of the principal varieties of fuel used in the United States, etc.”—-read before the American Philosophical Society of Philadelphia, in April, 1826. This is by far the most extended systematic and successful effort yet made in this interesting field of experimental inquiry, and may be of great utility for our iron establishments, which are all
, except the few on the eastern slope of the Cumberland mountains, at a great distance from our coal fields.
The general principle on which Mr. Bull's experiments were conducted for determining the comparative heat evolved in the combustion of a given weight of each would sustain the air of the room at a temperature of 10 deg. above the surrounding medium. To obviate the influence which the ordinary atmospheric changes of temperature and the winds would produce on the results by furnishing a surrounding srefrigerating medium of inconstant power,” the room in which the experiments were performed was surrounded by double walls, and the intermediate space sustained by artificial heat during the experiments, at a uniform temperature, and somewhat higher than the greatest natural temperature of the external atmosphere. The actual temperature of the inner and the outer rooms, during the experiments, was determined by common mercurial thermometers suspended in each, and the difference of temperature by Leslie's differential thermometer, the horizontal part of which traversed the inner wall or partition, leaving a bulb and upright stem on each side. The combustion was effected in a small upright cylindrical stove, furnished with forty-two feet of sheet iron pipe of two inches diameter, having in it several convolutions before it left the room. So completely was the heat generated in the process of combustion dissipated by the pipe, and emitted into the room, that a thermometer, the bulb of which was inserted in the pipe just before it entered the chimney, indicated the same temperature as the one which hung in the room. As the conducting power of the air, in relation to caloric, is influenced by its hygrometric state, care was taken to preserve it in a uniform condition in this respect. All the varieties of fuel operated on were dried previous to combustion at a temperature of 250 degs. Fahrenheit. Their solid contents were determined in the usual method for irregular bodies, by the volume of water, which a given volume by the usual admeasurement displaces, and the specific gravities by the hydrostatic balance. In the latter case, porous substances, which expand by the absorption of water, as the wood, were previously covered with a varnish having exactly the same specific gravity as water; in short, no precaution seems to have been omitted by this laborious and able experimenter, to guard against every source
of error, both in the construction of his apparatus and in the general conduct of his inquiries. The annexed table exhibits the results of his experiments.
It also appears from the investigations of Mr. Bull that one pound of charcoal of hickory, maple, oak and pine will keep up 10 deg. of heat for 15 hours, whereas Lehigh coal kept this heat only 13 hours and 10 minutes, and bituminous coal 9 hours and 20 minutes.