CONTENTS. IX 



ART. PAGE 



112. General Formula for all the Resistances. 209 



113. Flow of Water in Rivers and Canals 211 



114. Different Velocities in a Cross-Section 212 



115. Transverse Section of the Stream 215 



116. Mean Velocity : 216 



117. Ratio of Mean to Greatest Surface Velocity 216 



118. Processes for Gauging Streams 218 



119. Most Economical Form of Transverse Section. 221 



120. Trapezoidal Section of Least Resistance 222 



121. Uniform Motion 224 



122. Coefficients of Friction 226 



123. Variable Motion 228 



124. Bottom Velocity at which Scour Commences 232 



125. Transporting Power of Water 233 



126. Back Water 235 



127. River Bends 236 



Examples 237 



CHAPTEE III. 



MOTION OF ELASTIC FLUIDS. 



128. Work of the Expansion of Air 242 



129. Velocity of Efflux of Air according to Mariotte's Law 244 



130. Efflux of Moving Air 247 



131. Coefficient of Efflux 249 



132. The Quantity Discharged . 250 



133. Coefficient of Friction of Air 251 



134 Motion of Air in Long Pipes 252 



135. Law of the Expansion of Steam 254 



136. Work of Expansion of Steam 256 



137. Work of Steam at Efflux 257 



138. Work of Steam in the Expansive Engine 259 



Examples 260 



CHAPTER IV. 



HYDROSTATIC AND HYDRAULIC MACHINES. 



139. Definitions 263 



140. The Hydrostatic Bellows 263 



