Page:Popular Science Monthly Volume 38.djvu/172

160 furnace, which, is exactly like that already described; 3 is manoeuvring the lever, to one end of which the ladle containing the melted iron is suspended; 4 holds the handle and tips the ladle, thus regulating the pouring of the metal; i i, the hole from which the ladle k, forming the base of the second furnace, was taken for pouring; l, the upper part of the furnace removed; n, mold in which the iron is being poured."

Réaumur also describes a third apparatus for melting cast iron, which consists of a furnace of similar form to that just described, but without the removable ladle bottom. This furnace was supported on "trunnions" by a carriage mounted on wheels; at a proper height above the bottom was a "tap-hole," and on the opposite side an opening, or tuyère, for the nose of the bellows. The iron to be melted was (as in the last furnace) mixed directly with the fuel, and when it became fluid accumulated in the bottom of the furnace; as soon as all the iron was melted, the "taphole" was opened and the bellows removed; the whole body of the furnace was then turned on its "trunnions," and the metal run off through the "tap-hole" into "molds" placed to receive it. This furnace was at a later period called a "calabash," and it may be regarded as the direct progenitor of the modern foundry "cupola"; and it is not more than forty years since a very similar apparatus was in use in this country for melting brass; but in this the furnace, after the metal was melted, was suspended by its "trunnions" to a crane, and, being without a "tap-hole," the metal was run into the molds by inclining the furnace sufficiently to allow it to run over the top.

The reader must not infer that the primitive lever crane, illustrated in Fig. 8, was the only form known in the early part of the last century; as, on the contrary, Agricola, more than one hundred and fifty years before, described and illustrated several cranes of much more elaborate construction, some of which are quite similar in idea to foundry cranes in common use at the present day.

As in some degree illustrative of the rude picturesqueness of all the belongings of the old type of charcoal furnace, we have engraved (Fig. 9) a view of the remains of one situated on the Conemaugh River, in western Pennsylvania. The "hot-blast stove" which surmounts the "stack" is evidence that the spirit of modern progress has wrestled with the inevitable in vain, and the broken "blast-pipes," grass-grown "stack," and luxuriant surrounding vegetation, show that the breath of igneous life has passed away forever, and that Nature is claiming her own again.

The old colonial iron-works were of necessity located in valleys where advantage could be taken of a natural fall of water, or where a stream could be dammed at small expense; and, although when measured by the standards of our time, they were very