. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. ture into a glass. Figs. 293 and 294, represent around smalt furnace, in two verticalsections, at right angles to eachother. The fire-place is vaulted orarched; the flame orifice a, is in themiddle of the furnace; b is the feedhole ; c, a tunnel which serves as anash-pit, and to supply air; d, open-ings through which the air arrivesat the fuel, the wood being placedupon the vault; e, knee holes fortaking out the scoriae from the potbottoms; /, working orifices, withcast-iron plates
. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. ture into a glass. Figs. 293 and 294, represent around smalt furnace, in two verticalsections, at right angles to eachother. The fire-place is vaulted orarched; the flame orifice a, is in themiddle of the furnace; b is the feedhole ; c, a tunnel which serves as anash-pit, and to supply air; d, open-ings through which the air arrivesat the fuel, the wood being placedupon the vault; e, knee holes fortaking out the scoriae from the potbottoms; /, working orifices, withcast-iron plates g, in front of these are the additional out-Jets h. The smoke and flame passoff through the orifices i, which ter-Jnitinte in expanded flues, where thesand may be calcined or the woodmay be baked. Ei2;ht hours aresufficient for one vitrifying operation,during which the glass is stirredabout several times in the earthen melting pots. The preparation of the different shades of blue glass is considered a secret in thesmelting works; and marked with the following letters :—F F F C, the finest; F C,. 294
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Keywords: ., bookcentury1800, bookdecade1840, booksubje, booksubjecttechnology
