### Contents

 Density and Specific Gravity 2 The Properties of Matter 6 CHAPTER II 25 IV 48 Curvilinear Motion 57 The Pendulum 63 Simple Machines 70 113 73
 Velocity of Sound 277 Interference 279 Sympathetic Vibrations 282 Pitch 284 Vibrations of Strings 289 Overtones and Harmonics 292 Vibration of Air in Tubes 294 Quality or Timbre 297

 CHAPTER III 83 The Barometer 92 The AirPump and Condenser 98 Heat 119 CHAPTER V 161 Current Electricity 198 The Dynamo 212 Electrical Quantities 221 Current Induction 235 The Electric Light 250 Electric Motor and Telegraph 253 The Telephone and Microphone 256 CHAPTER VI 260 Sources of Sound 266 Transmission of Sound 268 Reflection and Refraction of Sound 270 Intensity and Loudness 273
 Harmony and Discord 299 Vibrating Rods Plates and Bells 300 Graphic and Optical Study of Sound 302 CHAPTER VII 306 The Propagation of Light Its Velocity 307 Photometry 312 Reflection of Light 315 Refraction of Light 329 Lenses 339 Dispersion 350 Color 356 Spectrum Analysis 360 Interference of Light 364 Optical Instruments 367 Index 375 Copyright

### Popular passages

Page 331 - When a ray of light passes from one medium to another, it is refracted so that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocities in the two media.
Page 222 - Resistance Inversely Proportional to Cross-Section. The resistance of a conductor is inversely proportional to its cross-sectional area. Hence the greater the cross-section of a wire the less is its resistance. Therefore, if two wires have the same length, but one has a cross-section three times that of the other, the resistance' of the former is one-third that of the latter.
Page 33 - Every body continues in its state of rest or of uniform motion in a straight line, except in so far as it is compelled by force to change that state.
Page 50 - Newton generalized the law of attraction into a statement that every particle of matter in the universe attracts every other particle with a force which varies directly as the product of their masses and inversely as the square of the distance between them; and he thence deduced the law of attraction for spherical shells of constant density.
Page 228 - The strength of the current is proportional to the tangent of the angle of deflection.
Page 33 - Change of motion is proportional to the impressed force and takes place in the direction of the straight line in which the force acts.
Page 112 - The loss of weight of a body immersed in a fluid is equal to the weight of the displaced fluid, or a body immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by it.
Page 224 - Such an electromotive force as would cause a current of one ampere to flow through a resistance of one ohm.
Page 315 - AC (Fig. 124), the greater part of it is reflected in a definite direction. The angle that the incident ray makes with the normal PB to the reflecting surface at the point of incidence is called the angle of incidence, as IBP ; and the angle between the reflected ray and this normal is the angle of reflection, as RBP.
Page 329 - The incident ray, the reflected ray, and the normal to the surface at the point of incidence, all lie in the same plane. When a ray of light is refracted, n sin <t> = n...