dollars and fifty cents to six dollars; and in Boston, at from six dollars and fifty cents to seven dollars. These are market prices, on which large manufacturers generally receive a discount of from five to ten per cent.

m. General Remarks on Fuel.-Wood is at present so abundant throughout the United States, that charcoal furnaces and forges may be carried on for a great length of time, without apparently diminishing its quantity; still, so rapidly are civilization and wealth progressing, so rapidly is the consumption of iron augmenting, that cur attention cannot be otherwise than forcibly turned to mineral fuel as a substitute for wood in the manufacture of iron. Peat or turf is not sufficiently distributed to deserve any attention. There are peat bogs in the States of New York, Michigan, Rhode Island, New Hampshire, and Maine, and possibly in other States; but its application in our country is so limited, and will probably, for some time to come, be so limited, that it hardly deserves our notice. In France, Germany, Bohemia, and Russia, peat is used for the manufacture of iron; but here, independent of any other cause, the price of turf would prevent its application for this purpose. In countries where no mineral coal exists, its application may be advantageous. The reasons we have given against the use of turf apply equally well against the use of brown coal. Some kinds of lignite constitute a good fuel in the puddling furnace, as well as in reheating and sheet ovens; but their application in the blast furnace is very limited. Lignites found in the United States are very properly used only for the manufacture of alum and copperas.

n. Of all the coal deposits, those of anthracite and bituminous character deserve our closest attention. Their utility in the manufacture of iron, and their extraordinary magnitude throughout the United States, give to the iron business of this country prospects the most flattering of those of any nation, or of any time. England was supposed to include, until recently, the great coal deposits of the world; but these shrink into insignificance when comparedwith the gigantic deposits of the United States. The amount of coal distributed throughout the world is as follows:

How great the prospect, how extensive and durable the basis of comfort, prosperity, and happiness, to the citizens of the United States, this immense wealth of mineral fuel discloses! The distribution of coal throughout the different States of the Union is as follows:

By this table, we find that England, Ireland, Scotland, and Wales united, do not contain so much coal as the State of Ohio. We have omitted, in the above estimate, the smaller coal tracts in different States, as not worth mentioning.

United States Coal Measurement.—

Ordinary estimate of bituminous coal: 28 bushels 1 ton at 2240 lbs.

In the South, bituminous coal is sold by the barrel, weighing

172 13 barrels = 1 ton.

In New York, as well as in Boston, and elsewhere in the East, a ton of coal 2000 lbs.

On the State Canal and Tidewater Canal, Pa., toll is levied at 1000 lbs.

In Pennsylvania, Ohio, and several other States, a bushel 80 lbs. of coal.

Nova Scotia coal is sold by the chaldron 3360 lbs., or 42 bushels.

In Boston, the retail chaldron is but 2500 or 2700 lbs.

If raw fuel is inclosed, with exclusion of atmospheric air, in an iron or any other retort, and if to this fuel we apply heat, a decomposition ensues, and the result of such decomposition varies according to the kind of matter with which the retort was charged. From the moment heat is applied, the elements of the matter separate, and, according to the temperature, form new compounds, which did not previously exist in the raw material. If we charge the retort with wood, the first compound which escapes is water; this existed in the wood either in the form of sap, that is, water combined with soluble matter, or as hygroscopic water, attracted and retained by the porous aggregation of the wood. Hydrogen and oxygen are then expelled, and form chiefly water, and partly other compositions. A small amount of oxygen and hydrogen is left, to form, by an increasing temperature, different compounds with carbon. Hydrogen combines with a small amount of carbon, to form carburetted hydrogen (the fire-damp of the coal pits); after that, a mixture of a great many compounds, consisting of carburetted hydrogen, tar, acetic acid, messit, or wood alcohol, creasote, naphtha, &c., is distilled, which can be condensed from its gaseous into a liquid state, by introducing it into a cold receiver. The same law which governs the distillation of wood, is applied to the distillation of turf, brown coal, bituminous coal, &c., with this difference in the product, that those minerals which contain the least water, hydrogen, and oxygen, will leave the greatest amount of carbon, inasmuch as carbon can not be evaporated, without access of another element with which it unites. After distillation, a certain amount of carbon is left, according to the preponderating quantity of the elements. If there should be a great deal of water, hydrogen, and oxygen in the raw material, a small amount of carbon will be left; should there be a large proportion of carbon in the fuel, a large amount of charcoal will remain. Wood, turf, and brown coal generally leave a charcoal in precisely the form in which the pieces were put into the retort; their porous structure permits the evolution of the gases

without disturbing their form. Bituminous coal is so close, and its aggregates so compact, that the escape of any matter from the interior is impossible; its bulk, therefore, is increased by the application of heat; the hydrogen and oxygen which escape form small cells, and the remaining carbon is spongy.

The presence of water and ashes, as well as of hydrogen and oxygen. to a large amount, in fuel, is detrimental to iron, even in the puddling and reheating furnaces; and still more injurious in the blast furnace, as we shall hereafter see. To avoid these influences, at least in the blast furnace, we must have recourse to the charring of the fuel; by distilling it, we get rid of the injurious admixtures.

V. Charring of Wood.

If a piece of wood is heated until it kindles, a flame issues, which is nourished by the decomposition of the wood; this decomposition is the result of heat, and is continued by the heat produced by the flame itself. Within the flame is a dark body, carbon, which does not burn until all the hydrogen which protects it is consumed; and only after this protection ceases, and after the oxygen of the atmosphere finds access to the ignited carbon, is the carbon consumed, when it disappears gradually, leaving more or less incombustible matter, i. e. white ashes. If the access of atmospheric air is prevented after the hydrogen and oxygen are expelled or consumed, a black coal, charcoal, will remain. This experiment can be made in a simple way. If we take a long chip of wood, and hold the flame high until it is properly kindled, and then turn the flame suddenly downwards into a narrow tube with a bottom, the wood burns only above the neck of the tube, and the part which is in the tube is extinguished, leaving a black charcoal. This is, in the main, the principle of charring: the gaseous matter of the wood is kindled ; its water driven off; hydrogen, oxygen, and a little carbon yield the heat by which they are expelled; the access of atmospheric air is then excluded, and charcoal remains.

There are various modes of charring wood, differing principally in arrangement and manipulation. Scientifically, there are but two methods that is, producing the heat for charring from the material to be charred; and applying exterior heat, by means of extra fuel, in the manner we employ it in distillation. We shall describe the different modes in historical order, and shall dwell mainly upon the most practical.

a. The most ancient way of making charcoal is, simply, to dig a

hole in some dry place; to fill it with wood, and to burn a part of the wood until sufficient heat is produced to char it thoroughly; the wood is then covered with sod, or sand, or coal dust, to keep the air out; the charcoal will remain in the pit. The proper time of throwing on the covering is a matter of practical importance. This mode of charring is very imperfect, and, at present, is practiced only among uncultivated nations; it makes bad, light fuel, and furnishes it only in small quantity.

b. Charring in Heaps, Kilns.-To build a kiln or heap, a dry, sandy, and, when possible, level spot, in the woods, is selected, protected from wind and gales, and as close to the cord wood as possible; the earth is to be leveled, dug, and tilled, to remove stones and stumps, and sufficiently large to permit the building of a heap of thirty feet in diameter. A circular space of from forty to fifty feet diameter will thus be required. Great care should be taken that no spring, or water of any kind, is in the neighborhood of the level, and that sudden gusts of rain shall not overflow it. When the ground is leveled, and pounded as solidly as possible, the hauling of cord-wood should be commenced; this wood must be piled vertically around the circumference of the hearth or level, as represented in Fig. 24. The opening a, sufficiently large for a sled to enter, is left on the most convenient part of the ground, accessible by horses or oxen.

Fig. 24.

Hauling the wood to the hearth.

After all the wood is put around the hearth, the heaviest billets always to be placed inside, the collier puts either one stick, or, what is better, three stout sticks of about ten feet in length, right in the centre of the hearth, fixes them firmly in the ground, and then fastens or binds them with withes, so as to form a chimney or draft-hole in the centre of the hearth, as seen in Fig. 25.

The collier then commences to set his kiln, or pit, as it is sometimes called, by ranging the heaviest billets around the centre, at first vertically, and then gradually in a slanting position by turning the butt, or thickest end of the wood, downwards. The wood should