. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. e e, {fig. 656,) areleft over the top arch of the fur-nace, whereby the draught of airmay receive a suitable grate of the fireplace extendsover the whole length of the fur-nace, fig. 657, from the door c tothe door _/, situated at the oppositeextremity. The furnace called gal-lery includes commonly 30 cucurbits,and in some establishments even52. Into each are introduced from56 to 70 pounds of ore, and 15 to-j-^-j-r-T-T I I r E^ ^^Z^^^^^ ^^ pounds of quicklime, a mixtur
. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. e e, {fig. 656,) areleft over the top arch of the fur-nace, whereby the draught of airmay receive a suitable grate of the fireplace extendsover the whole length of the fur-nace, fig. 657, from the door c tothe door _/, situated at the oppositeextremity. The furnace called gal-lery includes commonly 30 cucurbits,and in some establishments even52. Into each are introduced from56 to 70 pounds of ore, and 15 to-j-^-j-r-T-T I I r E^ ^^Z^^^^^ ^^ pounds of quicklime, a mixture ^TTrTT^!~t^\\ll(//r^4^^=!=-i^l ^^~^^^~^^, which fills no more than two thirds of the cucurbit; to the neck astoneware receiver is adapted, con-taining water to half its fire, at first moderate, is eventually pushed till the cucurbits are red hot. Theoperation being concluded, the contents of the receivers are poured out into a woodenbowl placed upon a plank above a bucket; the quicksilver falls to the bottom ofthe bowl, and the water draws over the black mercury, for so the substance that coats. 812 MERCURY. the inside of the receivers is called. This is considered to be a mixture of sulphuretand oxyde of mercury. The black mercury, taken out of the tub and dried, is distDledanew with excess of lime; after which the residuum in the retorts is thrown away, asuseless. Mudel furnaces of Mmaden.—Figs. 659 and 660 represent the great furnaces withaludels in use at Almaden, and anciently in Idria; for between the two establishmentsthere was in fact little difference before the year 1794. Figs. 659 and 662 present twovertical sections ; figs. 660 and 661 are two plans of two similar furnaces, conjoined in one body of brickwork. In the fourfigures the following objects are to beremarked : a door «, by which the woodis introduced into the fire-place h. Thisis perforated with holes for the passageof air; the ash-pit c is seen upper chamber, d, contains the mer-
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Keywords: ., bookcentury1800, bookdecade1840, booksubje, booksubjecttechnology
