. Transactions . density of the air and the amount of vertical ascent performed,together with the resistances of a frictional and allied character met withby the air circulating in any such split, constitute the resistances to beovercome by the beforementioned descending columns; excepting onlythe part of such force of the descending columns as is lost to the internalwork of the shafts and air-ways, by being required to expel the air frointhe top of the upcast shaft; and when this is added as a resistance, theentire resistances must, by. way of each split (taken separately) amountto the same f
. Transactions . density of the air and the amount of vertical ascent performed,together with the resistances of a frictional and allied character met withby the air circulating in any such split, constitute the resistances to beovercome by the beforementioned descending columns; excepting onlythe part of such force of the descending columns as is lost to the internalwork of the shafts and air-ways, by being required to expel the air frointhe top of the upcast shaft; and when this is added as a resistance, theentire resistances must, by. way of each split (taken separately) amountto the same force or pressure as the force arising from the descendingcolumns:—the forces and resistances, in each case, being computedeither in head of air column, or as an equivalent in pressure per unit ofsurface. This case shows the danger of connecting the ventilation of twocollieries, excepting under certain conditions, which are essential tosafety in doing so. These conditions will be pointed out in the sequel. NV A <€■///,f-y 1 A . I . ;i, N* 10 Vol 12
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Keywords: ., bookcentury1800, booksubjectmechan, booksubjectmineralindustries
