. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. furnace con-structed by Messrs. Anfrye and dArcet,which gives some peculiar facilities andeconomy to the ancient process by fire. Ithad oriifinally a small pair of bellows at-tached to it, for raisin? the heat rapidly tothe proper vitrifying pitch. The furnace,17^ inches high, and 7J inches wide, madeof pottery or tine clay, is represented , suppoi ted upon a table, having a pairof bellows beneath it. The laboratory isat b, the blow-pipe of the bellows at d,with a stop-cock,
. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. furnace con-structed by Messrs. Anfrye and dArcet,which gives some peculiar facilities andeconomy to the ancient process by fire. Ithad oriifinally a small pair of bellows at-tached to it, for raisin? the heat rapidly tothe proper vitrifying pitch. The furnace,17^ inches high, and 7J inches wide, madeof pottery or tine clay, is represented , suppoi ted upon a table, having a pairof bellows beneath it. The laboratory isat b, the blow-pipe of the bellows at d,with a stop-cock, and the dome is sur-mounted by a chimney a c, in whose low-er part there is an opening with a slidingdoor, for the introduction of the charcoalfuel. The furnace is formed in threepieces; a dome, a body, and an pair of tongs, a stokins hook, and cupel,are seen to the right hand, and the plan ofthe stone-ware grate, pierced with conicalholes, and a poker, are seen to the left. Thisgrate suits the furnace represented underAssay. The following are comparative experiments made by means of this FUSTIAN. 543 Numbers. Silver employed. Lead employed. Time of assay. Standards. Charcoal used. 1234 1 Grain. 4 Grains. 12 minutes. 11 13 10 947 milliemes. 950 949 949 173 Each assay was therefore performed at an average in llj minutes, and not much morethan a quarter of a pound of charcoal was used. An experiment of verification in theordinary assay furnace showed the standard to be 949 thousandths. This furnace becomes a very convenient one for melting small quantities of metals inanalyses, by removina the muffle, and closing the several apertures with their appropriatestoppers. A small pedestal may be then set in the middle of the grate, to support a cru-cible, which may be introduced through the opening h. Coke may also be used as fuel,either by itself or mixed with charcoal. For descriptions of various furnaces, seeAssay ; Beer ; Copper ; Evaporation ; Iro
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