PREFACE 



A COMPLETE survey of the theory of sound would lead into 

 -^^- many fields, physical, physiological, psychological, aesthetic. 

 The present treatise has a more modest aim, in that it is 

 devoted mainly to the dynamical aspect of the subject. It is 

 accordingly to a great extent mathematical, but I have tried to 

 restrict myself to methods and processes which shall be as 

 simple and direct as is possible, regard being had to the nature 

 of the questions treated. I hope therefore that the book may 

 fairly be described as elementary, and that it may serve as a 

 stepping stone to the study of the writings of Helmholtz and 

 Lord Rayleigh, to which I am myself indebted for almost all 

 that I know of the subject. 



The limitation of methods has involved some sacrifices. 

 Various topics of interest have had to be omitted, whilst 

 others are treated only in outline, but I trust that enough 

 remains to afford a connected view of the subject in at all events 

 its more important branches. In the latter part of the book 

 a number of questions arise which it is hardly possible 

 to deal with according to the stricter canons even of mathe- 

 matical physics. Some recourse to intuitional assumptions is 

 inevitable, and if in order to bring such questions within the 

 scope of this treatise I have occasionally carried this license 

 a little further than is customary, I would plead that this is 

 not altogether a defect, since attention is thereby concentrated 

 on those features which are most important from the physical 

 point of view. 



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