CONTENTS. XI 



SECTION II. 



Page 



Velocity of Water in Ditches 192 



Leveling Instruments 194 



SECTION III. 



HYDRAULIC MACHINES. 



Archimedean Screw 196 



Archimedean Root-washer 197 



Pumps 198 



Water-ram 200 



Water-engines 202 



Flash-wheel 203 



SECTION IV. 



WAVES. 



Nature of Waves 204 



The Water not progressive 205 



Breadth and Velocity of Waves 206 



Preventing the Inroads of Waves 208 



SECTION V. 



Contents of Cisterns 210 



Rule for determining the Contents 211 



Determining their Size 212 



PART III. 



PNEUMATIC 

 CHAPTER I. 



PRESSURE OF AIR. 



Height and Weight of the Atmosphere 213 



The Barometer 216 



The Syphon 218 



CHAPTER II. 



MOTION OF AIK. 

 SECTION I. 



Winds— Force of Wind 221 



Wind-mills for Farms 223 



Causes of Wind 227 



