A patent recently granted in America, to Mr. C. Lewis, (of Pine Creek, Alleghany County, Pennsylvania,) for refining pig iron, seems also to be well deserving of the attention of the English manufacturer. The process is chiefly effected by mineral coal, uncoked, but in such a manner, that the metal while in a state of fusion is not brought into contact with the mineral coal. A reverberatory furnace is employed; the mineral coals are put on the grate-bars, and when the furnace has acquired a melting heat, a door at the side of the furnace is opened, through which a bushel of charcoal is introduced into a basin ten inches deep, previously covered with a stratum of silicious sand; over the charcoal is distributed, so as to cover it, a bushel of hammer or forge cinder, and then about a ton of pig metal, so laid around the basin as to leave a space between each pig; thereby a greater surface of the metal is exposed to the action of the flame. The fire in the grate is now to be well supplied, and maintained; and all access of air prevented, except through the grate.

In about half an hour, the metal will be nearly melted, which, when the workman perceives to be the case, he drags, by means of an iron rabble passed through a hole in the door, the whole of the metal from the sides, into the basin. He then introduces from three quarters to one bushel of charcoal upon the surface of the metal in fusion. The fire being kept up, and the metal frequently stirred, it will, in half an hour after the whole is melted down, be sufficiently decarbonized to let it run out of the furnace. The consumption of mineral coal in this operation is from 15 to 18 bushels, and two of charcoal of wood, to each ton of metal; and the ton of metal is obtained from only 22 cwts. of pigs. Owing to the intense heat of the furnace, the volatile parts of the coal are consumed, or pass along the roof of the furnace into the flue, while the surface of the metal is protected by the charcoal and the scoriae, which in all cases keep uppermost without incorporating with the metal. Refining after the above way will be of great advantage to forges that make their blooms by means of charcoal, as it will greatly facilitate the procedure, and lessen the quantity of charcoal used. The iron made in the manner described is said to be quite malleable, close in texture, and fibrous.

It is worthy of observation, that this furnace requires no machinery attached to it, and the process appears calculated to effect some important savings to the manufacturer.