Indian Science and Technology in the Eighteenth Century: Some Contemporary European Accounts c23.s5.t3.7

c23.s5.t3.7

To construct it practically—dig a fosse 3 feet deep in the annexed form (Diagram 3, fig 2) the semicircular part of which contains the furnace B, the walls CCC being composed of unburnt bricks of large dimensions; the first structure is crude, preserving only an approximation to the required form, the interior being afterwards cut away; a large stone capable of containing heat is placed at the bottom; and in this state it is suffered to remain until thoroughly dry; the next operation is performed by a more skilful artist who cuts away the interior, and plasters it with clay, using the measures above described to adjust its dimensions; he first finishes the top, and from the centre of the back part of it, he drops a plummet, to ascertain the spot where the centre of the front part of the stone is to rest; this plummet line corresponds with the perpendicular CD of the geometrical figures 1 and 2—and thus he obtains not only the required obliquity of the furnace, but the points most essential for the adjustment of all the rest.