Fig. 231.—Primitive Furnace for Smelting Iron.
This composition reproduces with tolerable accuracy the model in relief constructed by the author. The furnace is shown; it is nothing but a simple cavity surmounted by a conical chimney-funnel, and placed against the side of a hill. Steps made of rough stone, placed on each side of the mound, enable the workmen to mount to the summit. The height of the funnel is about 9 feet. At the side of the furnace stands the hut for the labourers, constructed of a number of round poles placed side by side; for centuries past huts of this kind have been erected in almost every country.
On the right, in the foreground, we may notice a heap of charcoal intended to be placed in the furnace in order to reduce the ore; on the left, there is the store of ore called in the ironworks the ore-pen. The provision of iron-ore is enclosed between four wooden slabs, forming a quadrangular space. In the centre are the scoriæ which result from the operations carried on. A workman is extracting the cake of spongy iron from the ashes of the furnace; another is hammering on the anvil a piece of iron drawn from the furnace in order to forge it into a bar. Round the furnace various implements are scattered about, such as the anvil, the pincers, the hammer, &c. All the instruments are designed from various specimens found by the author.
After these explanations, we may now give some extracts from M. Quiquerez' work, and we trust our readers will find no difficulty in comprehending the details given by the learned engineer, describing the primitive furnaces for the extraction of iron which he discovered in the Bernese Jura.
M. Quiquerez has remarked two kinds of primitive furnaces for the fabrication of iron, or, rather, two stages of improvement in their construction. The first sort, that which the author considers as dating back to the most remote antiquity, is not so numerous as the others; the second kind form the largest number of those which he has explored.
"Furnaces of the first kind," says M. Quiquerez, "consisted of nothing but a small cylindrical excavation of no great regularity in shape, with a cup-shaped bottom, hollowed out in the side of a hill so as to give more natural height on one side; the front of the furnace was closed up by fire-proof clay, supported with stones. This cavity was plastered over with 4 to 6 inches of clay, generally of a whitish colour, which became red after coming in contact with the fire. These smelting-furnaces were not more than 12 to 18 inches in depth, as seemed to be shown by the upper edges being rounded and more or less scoriated. The front, which was always more or less broken, had an opening at its base to admit a current of air, and to allow the workmen to deal with the melted material; but this opening seems to show that the piece of metal which had been formed during the operation must have been extracted by breaking in the front.
"The second kind of furnace, which is by far the most numerously found and widely distributed, is, in fact, nothing but an improvement of that which preceded it, the edges of the furnace or crucible being considerably raised in height. They vary in depth from 7½ to 8 feet, with a diameter of most irregular dimensions, from 18 inches upwards, and a thickness of 12 inches to 7 feet. They are likewise formed of fire-proof clay, and their average capacity is about 25 gallons.