xviii LIST OF ILLUSTRATIONS 



FIGURE PAGE 



167. Strings Stretched across the Table 328 



168. Cello and Violin 329 



169. End of a Clarinet Showing Reed 330 



170. Squawker Made of an Oat Straw 331 



171. Fife Showing Changing Length of Air Column .... 332 



172. String Vibrating as a Whole and in Halves 335 



173. The Larynx . 336 



174. Diagram of a Phonograph 336 



175. Diagram to Locate a Gun by Sound 338 



CHAPTER XV 



176. A Pair of Scales 340 



177. The Crowbar in Use 340 



178. The Arm Showing Triceps Muscle . 342 



179. Levers of Classes i, 2, and 3 . . . . . . . . 342 



180. A Hammer as a Bent Lever . . 342 



181. The Wheelbarrow as a Lever 343 



182. Wheel and Axle Used in Steering a Boat 343 



183. A Windlass 344 



184. A Capstan 344 



185. GearWheels . . . . . . . . . . .345 



186. A Hand Derrick . 345 



187. The Sprocket Wheel and Chain on a Bicycle .... 346 



1 88. A Single-wheeled Pulley 347 



189. Two Double Pulleys 347 



190. Rolling a Barrel up an Inclined Plane . . . . . . 348 



191. The Chisel as an Inclined Plane 349 



192. A Screw Jack . . . . 349 



193. Turning a Nut on a Bolt with a Wrench 350 



194. A Planisphere. Part I facing 356 



195. A Planisphere. Part II . . . . , . . . facing 357 



