CHAPTER XVIII.

195. Pumping and Pumps 254 196. Resistances of Pumps and Main—Dynamic Head 258 197. Duty of Pumping-engines 260 198. Data to be Observed in Pumping-engine Tests 261 199. Basis of Computations for Duty 262 200. Heat-units and Ash in 100 Pounds of Coal, and Amount of Work Equivalent to a Heat-unit 262 201. Three Methods of Estimating Duty 265 202. Trial Test and Duty of Allis Pumping-engine 265 203. Conditions Affecting Duty of Pumping-engines 266 204. Speeds and Duties of Modern Pumping-engines 266