CONTENTS
CHAPTER I | |
The Nerves and Sensation—Production and Propagation of Sonorous Motion—Experimentson Sounding Bodies placed in Vacuo—Deadening ofSound by Hydrogen—Action of Hydrogen on the Voice—Propagationof Sound through Air of Varying Density—Reflection of Sound—Echoes—Refractionof Sound—Diffraction of Sound; Case of ErithVillage and Church—Influence of Temperature on Velocity—Influenceof Density on Elasticity—Newton’s Calculation of Velocity—ThermalChanges Produced by the Sonorous Wave—Laplace’sCorrection of Newton’s Formula—Ratio of Specific Heats at ConstantPressure and at Constant Volume deduced from Velocities ofSound—Mechanical Equivalent of Heat deduced from this Ratio—Inferencethat Atmospheric Air Possesses no Sensible Power to RadiateHeat—Velocity of Sound in Different Gases—Velocity in Liquids andSolids—Influence of Molecular Structure on the Velocity of Sound. | [31] |
| Summary of Chapter I | [77] |
CHAPTER II | |
Physical Distinction between Noise and Music—A Musical Tone Producedby Periodic, Noise Produced by Unperiodic, Impulses—Production ofMusical Sounds by Taps—Production of Musical Sounds by Puffs—Definitionof Pitch in Music—Vibrations of a Tuning-Fork; theirGraphic Representation on Smoked Glass—Optical Expression of theVibrations of a Tuning-Fork—Description of the Siren—Limits ofthe Ear; Highest and Deepest Tones—Rapidity of Vibration Determinedby the Siren—Determination of the Lengths of Sonorous Waves—Wave-Lengthsof the Voice in Man and Woman—Transmission ofMusical Sounds through Liquids and Solids. | [82] |
| Summary of Chapter II | [117] |
CHAPTER III | |
Vibration of Strings—How employed in Music—Influence of Sound-Boards—Lawsof Vibrating String—Combination of Direct and ReflectedPulses—Stationary and Progressive Waves—Nodes and Ventral Segments—Applicationof Results to the Vibrations of Musical Strings—Experimentsof Melde—Springs set in Vibration by Tuning-Forks—Lawsof Vibration thus demonstrated—Harmonic Tones of Strings—Definitionsof Timbre or Quality, or Overtones and Clang—Abolitionof Special Harmonies—Conditions which affect the Intensity of theHarmonic Tones—Optical Examination of the Vibrations of a Piano-Wire | [120] |
| Summary of Chapter III | [161] |
CHAPTER IV | |
Vibrations of a Rod fixed at Both Ends: its Subdivisions and CorrespondingOvertones—Vibrations of a Rod fixed at One End—The Kaleidophone—TheIron Fiddle and Musical Box—Vibrations of a Rod free at Both Ends—TheClaque-bois and Glass Harmonica—Vibrations of a Tuning-Fork:its Subdivisions and Overtones—Vibrations of Square Plates—Chladni’sDiscoveries—Wheatstone’s Analysis of the Vibrations of Plates—Chladni’sFigures—Vibrations of Disks and Bells—Experiments ofFaraday and Strehlke. | [165] |
| Summary of Chapter IV | [196] |
CHAPTER V | |
Longitudinal Vibrations of a Wire—Relative Velocities of Sound in Brassand Iron—Longitudinal Vibrations of Rods fixed at One End—Of Rodsfree at Both Ends—Divisions and Overtones of Rods vibrating longitudinally—Examinationof Vibrating Bars by Polarized Light—Determinationof Velocity of Sound in Solids—Resonance—Vibrations of StoppedPipes: their Divisions and Overtones—Relation of the Tones of StoppedPipes to those of Open Pipes—Condition of Column of Air within aSounding Organ-Pipe—Reeds and Reed-Pipes—The Voice—Overtonesof the Vocal Chords—The Vowel Sounds—Kundt’s Experiments—NewMethods of determining the Velocity of Sound. | [200] |
| Summary of Chapter V | [254] |
CHAPTER VI | |
Singing Flames—Influence of the Tube surrounding the Flame—Influenceof Size of Flame—Harmonic Notes of Flames—Effect of UnisonantNotes on Singing Flames—Action of Sound on Naked Flames—Experimentswith Fish-Tail and Bat’s-Wing Burners—Experiments on TallFlames—Extraordinary Delicacy of Flames as Acoustic Reagents—TheVowel-Flame—Action of Conversational Tones upon Flames—Action ofMusical Sounds on Smoke-Jets—Constitution of Water-Jets—Plateau’sTheory of the Resolution of a Liquid Vein into Drops—Action of MusicalSounds on Water-Jets—A Liquid Vein may compete in Point ofDelicacy with the Ear | [260] |
| Summary of Chapter VI | [301] |
CHAPTER VII | |
PART I | |
RESEARCHES ON THE ACOUSTIC TRANSPARENCY OF THE ATMOSPHERE INRELATION TO THE QUESTION OF FOG-SIGNALLING | |
Introduction—Instruments and Observations—Contradictory Results fromthe 19th of May to the 1st of July inclusive—Solution of Contradictions—AërialReflection and its Causes—Aërial Echoes—AcousticClouds—Experimental Demonstration of Stoppage of Sound by AërialReflection | [305] |
PART II | |
INVESTIGATION OF THE CAUSES WHICH HAVE HITHERTO BEEN SUPPOSEDEFFECTIVE IN PREVENTING THE TRANSMISSION OF SOUNDTHROUGH THE ATMOSPHERE | |
Action of Hail and Rain—Action of Snow—Action of Fog; Observationsin London—Experiments on Artificial Fogs—Observations on Fogs at theSouth Foreland—Action of Wind—Atmospheric Selection—Influence ofSound-Shadow | [341] |
| Summary of Chapter VII | [374] |
CHAPTER VIII | |
Law of Vibratory Motions in Water and Air—Superposition of Vibrations—Interferenceof Sonorous Waves—Destruction of Sound by Sound—CombinedAction of Two Sounds nearly in Unison with each other—Theoryof Beats—Optical Illustration of the Principle of Interference—Augmentationof Intensity by Partial Extinction of Vibrations—ResultantTones—Conditions of their Production—Experimental Illustrations—Difference-Tonesand Summation-Tones—Theories of Youngand Helmholtz | [377] |
| Summary of Chapter VIII | [407] |
CHAPTER IX | |
Combination of Musical Sounds—The smaller the Two Numbers which expressthe Ratio of their Rates of Vibration, the more perfect is the Harmonyof Two Sounds—Notions of the Pythagoreans regarding MusicalConsonance—Euler’s Theory of Consonance—Theory of Helmholtz—Dissonancedue to Beats—Interference of Primary Tones and of Overtones—Mechanismof Hearing—Schultze’s Bristles—The Otoliths—Corti’sFibres—Graphic Representation of Consonance and Dissonance—MusicalChords—The Diatonic Scale—Optical Illustration of MusicalIntervals—Lissajous’s Figures—Sympathetic Vibrations—VariousModes of illustrating the Composition of Vibrations | [410] |
| Summary of Chapter IX | [450] |
APPENDIX I | |
On the Influence of Musical Sounds on the Flame of a Jet ofCoal-gas. By John le Conte, M.D. | [454] |
APPENDIX II | |
| On Acoustic Reversibility | [461] |
| INDEX | [471] |
| ILLUSTRATION—Fog-Siren | [Frontispiece] |
Fog-Siren