. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. \^y,-r-y ^?h,i&U--€i^ Fig. 1321 is a vertical section of the work in the first stage of its progress. Upon the ring a a of dome is, in the first place, built of bricks and loam, generally some 4 in. thick. Themoulder is guided in the construction of this dome by the interior loam board, sustained by thespindle. The external surface ought to be everywhere about 2 in. distant from the surface describedby the board ee. Before building up the dome to the crown, coals are placed in the floor within it
. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. \^y,-r-y ^?h,i&U--€i^ Fig. 1321 is a vertical section of the work in the first stage of its progress. Upon the ring a a of dome is, in the first place, built of bricks and loam, generally some 4 in. thick. Themoulder is guided in the construction of this dome by the interior loam board, sustained by thespindle. The external surface ought to be everywhere about 2 in. distant from the surface describedby the board ee. Before building up the dome to the crown, coals are placed in the floor within it,which are afterwards kindled fur drying the work. The crown is then nearly completed, leavingonly a small space round the spindle, to allow of ventilation when the combustion is going this aperture the moulder is enabled fco manage his fire, so as to cheek its progress, if neces- 648 sary. The consumption ought to be very slow, so as to allow of the heat taking effect upon theentire mass. Over the brick dome a pasty layer of core loam o o is applied; for it is in fact the core that isnow being formed. The surface is finished off by a smoothing coating of wet loam, the redundanciesall over the surface being swept off by the board in its revolution. Upon this siuface the insideof the pan is cast. The fire is now kindled, and as the surface of the 1^23. mould becomes dry, it is paintedover by a brush with a mixture ofwater and charcoal powder, with alittle clay additional. This operationprevents adhesion between the sur-faces of the core and the coat ofloam applied to it. The core board having been re-moved, it is replaced, as in Fig. 1322,by the thickness board /, Fig. 1320,of which the edge describes theexternal surface of the pan, and, asalready remarked, simply rubsagainst the knee formed round thebase of the core. Another layer ofloam a a is then spread over the
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectenginee, bookyear1879
