Introduction.Feed-water: Analysis—Systematic control of supplies—Softening—Scale and grease troubles—Preheating—Thermal Storage.Fuel: Sampling—Testing—Systematic control of supplies—Suitability for boiler-furnace.Air: Preheating primary and secondary air supply.Boilers and Furnaces: Types of—Setting—Hand-firingv.mechanical stoking—Losses by radiation and air-leakage—Smoke prevention.Steam: Superheating—Condensation and radiation losses.Waste Gases: Heat losses in—Sampling—Testing—Systematic control of.Draught and Regulation of Air Supplies: Naturalv.artificial graught.