A Practical Treatise on Friction of Air in Mines

air circulating air in mines air increases air per minute air-way 10 feet amount of friction amount of ventilation Anemometer applied barometer bing surface changes of density cloth co-efficient of friction collieries Columbia College Cool cubic feet cubic foot downcast shaft engravings extent of rubbing feet of air feet per minute feet square foot of sectional formulæ friction of air heat horse-power hygrometer Hypsometry inches of mercury intakes Iron large air-way length long split overcome the friction Peclet pipes Practical pressure per foot proportion quantity of air reduced required to overcome revised and enlarged rise or dip rise splits rubbing surface exposed sectional area small air-way splits of air splitting the air square feet square foot Steam Engine Telegraphy temperature thousands of feet tilation tion total pressure total quantity Treatise U. S. Navy upcast shaft velocity in feet velocity in thousands ventilat ventilating pressure water gauge weight