The singer faces an audience or a strange audience for the first time, and the first unfavorable and disconcertive effect travels over the nerves to the respiratory organs. Regular breathing is at such times one of the best ways to allay the undue excitement caused by the unusual surroundings. Before beginning to sing the artist should, and on such occasions with conscious artistry, immediately reëstablish control of respiration by taking a few deep breaths. I have said before that the borderline between the physiology of voice-production and the psychology of song is a narrow one--whereof the above cure for stage-fright is but another case in point. CHAPTER V THE PHYSIOLOGY AND PSYCHOLOGY OF VOICE-PRODUCTION Above this chapter I might well have placed the following lines which George Eliot wrote above Chapter XXXI. of "Middlemarch." How will you know the pitch of that great bell, Too large for you to stir? Let but a flute Play 'neath the fine-mixed metal! Listen close Till the right note flows forth, a silvery rill: Then shall the huge bell tremble--then the mass With myriad waves concurrent shall respond In low, soft unison. The lines telling of the great bell stirred by the note of a flute played at the proper pitch suggest the moving power that lies in sympathetic vibration. The first time a military body crossed the Brooklyn Bridge, the spectators were surprised to hear the order given for the soldiers to march out of step. They had expected to be thrilled by the sight of a thousand men crossing the great structure in measured tread, with band playing and colors flying. They did not know that the structure, being a suspension bridge, might have been weakened and possibly destroyed by the force of rhythmic oscillation. Yet the accumulated force in the tramp of a thousand men is no greater than that which lies in the sympathetic vibrations of a musical note. Every metal structure has its note, and it is an old engineering saw that a huge structure like the Brooklyn Bridge eventually could be destroyed by the cumulative force of sympathetic vibration evoked by a musical instrument constantly reiterating the note of the bridge. Sound has three dimensions: pitch, loudness and timbre. _Pitch_ depends upon the _frequency_ of vibrations. The more rapid the vibrations, the higher the pitch. _Loudness_ is determined by the _amplitude_ of the vibrations. As their length or "excursion" increases, so does the sound gain in loudness. Conversely, the diminution in the size of vibrations causes corresponding decrease of loudness. Differences in the _shapes_ of vibrations cause differences in quality or _timbre_.