The Ventilation of Coal Mines

according air column air passing airways area and rubbing Brevet calculation circulate cloth co-efficient of friction collieries common pressure cube root cubic feet Degs diameter dimensions dip and rise Divisions effect of split feet of air feet per minute figures in column final velocity fire damp foot of rubbing formula gases give given Illustrated intake ksv² long split mines motive column multiplied NOSTRAND'S PUBLICATIONS obtained pass equal quantities Plympton pounds per square power required PRESCOTT pressure or power pressure required producing the ventilation proportion quantity of air quantity passing relative powers relative pressures required to pass result return air revised and enlarged rise split road 6 ft rubbing surface rule specific gravity splits subject splitting the air square foot Steam temperature tion total quantity typical road U. S. Navy underground unequal splitting University of Michigan upcast shafts ventilating pressure water gauge weight yards long ха