A short time ago, a patent was taken out in America, by Mr. B. Howell, of Philadelphia, for an improvement in a "bloomery furnace," "by means of which, and the use of anthracite coal exclusively for fuel, iron ore is directly converted into malleable iron." As this invention would be of immense importance to the country, if it could be brought successfully into operation, (and we can discover no reason why it should not,) we deem it right not to omit giving a description of it in this work.

The specification, after adverting to the drawings, states, " By these, and the notes and references appended thereto, it will be seen that this furnace combines within itself the advantages of a close furnace and an open fire; in this respect differing essentially from any other now in use for similar objects. In the upper or close portion, being all that above the hearth, with anthracite coal excited by a proper blast, a degree of heat is obtained much greater than can possibly be generated in the ordinary fire with charcoal; while the lower portion opening into the hearth, and permitting the free action of blast upon the burthen, performs all the offices of the open fire, or forge. The size of the furnace and the proportions may be varied, if the principle of the close and open fire be retained. The furnace being first heated up in the manner of a common cupola, the process is thus conducted: the coal having settled sufficiently for that purpose, it is charged with the proper burthen of ore, which will vary according to the quality and kind.

The charges are then continued alternately of coal and ore.

The ore soon arrives at the tuyeres in a state of partial fusion, and is then, by the intense heat of that part of the furnace, quickly separated from its earths, and then rapidly descending into and below the direct action of the blast, a large part of which is driven out at the open front, first passing over that portion of the ore which has reached the hearth, it is thereby brought, in the language of the workmen, "to nature," or, in other words, into malleable iron. As it sinks into the region of the blast, the small masses may be driven into one, and a loup shaped by giving a proper direction to the pipes at the different tuyeres, and the loup can be removed with a proper instrument; another instrument, or strong iron bars, being introduced at B, to hold up the burthen while this is doing. The loup may be drawn into a bloom under a forge hammer, or passed through rollers. In either operation, it will, of course, be necessary to renew the heats, which may be done in a common chaffery, or in a heating furnace. This process is continued at the pleasure of the workmen, and as soon as a quantity sufficient for a loup accumulates, it is withdrawn, as above described.

In the early stage of the operation, it will be necessary to charge the furnace, nearly, or quite to the top; but as the heat increases, the height of the coal may be gradually diminished; and at a very high temperature, from two to three feet of coal will be found sufficient. The cinder produced in this way will bear working a second time; an appropriate flue facilitates the operation, and as it is first fused, and sinks, and is thus interposed between the iron at the bottom of the hearth, and the coal, it contributes to prevent a mixture of the two. Holes may or may not be left in the sides of the furnace for the introduction of bars to aid in detaching the iron from the bottom and sides; but this will often be necessary, if the back of the furnace be thrown sufficiently forward, and a proper direction be given to the blast; for which purpose, tuyeres are placed in different positions on three sides of the furnace, and at different elevations. One or two pipes may be used at pleasure. From the foregoing, it must be obvious that by the rapidity of the process, the saving thereby of time and labour the substitution of a cheaper, more powerful, and abundant fuel for that now in use, and which is so made applicable to this object by the peculiar construction of this furnace, - a great and important improvement has been effected in the conversion of iron ore into malleable iron.

The following drawings, Figs. 1, 2, 3, represent an elevation, and vertical and horizontal sections, all drawn to a scale of one inch to three feet, the same letters referring to corresponding parts of each. A is the tunnel head, where the furnace is charged; to be provided with a cover, which is placed on in the intervals of charging, when the coal is low. B a projecting, open, hollow hearth, for the reception of cinder and iron, with a cinder hole at C, to be opened when it is wished to draw off the cinder. D D are tuyeres for the introduction of the blast, placed in different positions on three sides of the furnace, and at different elevations, to vary the direction of the blast at different stages of the process. The back and front walls may both or either be thrown or inclined somewhat more inward than is represented in the drawing, and as indicated by the dotted line on the vertical section; and with advantage when the ore is not very pure, and makes much cinder. The furnace is to have over it a brick canopy or chimney, to aid in carrying off the gas given out by the coal.

The furnace is lined with fire brick, and is cased with cast-iron plates, secured by strong bolts, keys, and screws, and between the casing and the lining, common brick, with a thin packing of sand; the latter, to prevent injury from expansion. In a letter to Dr. Jones, (the editor of the Journal of the Franklin Institute) Mr. Howell, the patentee of the furnace just described, states that he had completely succeeded in making bar iron, and even nails with it, without suffering the iron to cool; and that practical forgemen, who performed the manual labour, were astonished beyond measure at the result; the iron being as good as that made at the neighbouring forges in the old way.

Fig. 1.

Fig. 2.