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THE STEAM-ENGINE. 



(FOURTH LECTURE.) 



Analysis of Coal. Process of Combustion. Heat evolved in it. Form and Structure of Boiler. 

 Wagon-Boiler Furnace Method of Feeding it. Combustion of Gas in Flues. Williams' 

 Patent for Method of Consuming unburned Gases. Construction of Grate and Ash Pit. Magni- 

 tude of Heating Surface of Boiler. Stoam Space and Water-Space in Boiler. Position of Flues. 

 Method of Feeding Boiler. Method of Indicating the Level of Water in Boiler. Lever 

 Gauges. Self-Regulating Feeders. Steam-Gauge. Barometer-Gauge. Watt's Invention of 

 the Indicator. Counter. Safety- Valve. Fusible Plugs. Self Regulating Damper. Brunton's 

 Self- Regulating Furnace. Gross and Useful Effect of an Engine. Power and Duty of Engiues. 

 Horse-Power of Steam- Engines. Table exhibiting the Mechanical Power of Water converted 

 into Steam at various Pressures. Evaporation Proportional to Horse-Power. Sources of Loss 

 of Power. Absence of good Practical Rules for Power. Common Rules followed by Engine- 

 Makers. Duty distinguished from Power. Duty of Boilers. Proportion of Stroke to Diameter 

 of Cylinder. Duty of Engines. Cornish System of Inspection. Table showing the Improve- 

 ment of Cornish Engines. Beneficial Effects of Cornish Inspection. Successive Improvements 

 on which the increased Duty of Engines depends, traced by John Taylor in his " Records of 

 Mining." 



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