There is a very close analogy between sound and light. For instance, both possess the same properties of being refracted. We say certain surfaces absorb so much light and reflect so much back. It is exactly the same with sound; a smooth or polished wall or ceiling will reflect a part of the sound back again, while curtains, carpets, etc., will have a tendency to absorb to a greater or lesser degree, according to their varying surfaces. While every tone travels through the air with equal rapidity, each tone has its own length. Exactly the same is true concerning colour vibration. A sounding-board in a piano, the woodwork in a violin, the roof of the mouth, and the resonant head chambers used in voice production, all act to give increased volume in sound production, but do not change the wave length or cause greater velocity of movement. Resonance, however, means greater volume of sound, and because of increased volume there will be increased molecular vibration in the atmosphere.
Man's physical senses bring him into the closest relationship with his outer environment. His five senses may be summed up as differentiations of one sense, namely, that of touch. Touch, in the first degree, brings man into the closest relation to material things. Next we find that various things coming in touch with the palate act on the sense of taste. Again, by the way in which different perfumes and odours come in touch with the olfactory nerve, the sense of smell is made evident. In a still greater degree, by the way that atmospheric vibration comes in touch with the tympanum or drum of the ear, the sense of hearing is affected, and the last or most remote degree of touch is the way that colour or light vibration comes in touch with the optic nerve of the eye. It must therefore be evident that four of the senses - viz., taste, smell, hearing, and seeing - are only different degrees of the one vital sense we call touch; but it is with the sense of hearing and seeing that we have most to do in this book. There are two peculiarities that I should like to make clear concerning the sense of sight and the sense of hearing. The eye receives pictures from without, and, as a general thing, the pictures it receives affect man's mind far more than they do his feelings. Sight is the sense of touch that is farthest removed from man, and his life is usually not nearly as much disturbed by what he sees as by what he hears. In other words, seeing is more of a mental process than any one or all of the other senses. Hearing, however, seems to be more of a process of feeling. Let me illustrate it in this way: we might see a building burning at a distance without our feelings being affected to any marked degree by it. But if we were close to it and could hear the cries of distress coming from those unable to escape, not only would our minds be quickened, but all our feelings would be aroused. With the aid of our eyes we take in pictures of objective life. With the aid of our ears we come in touch with man's more subjective life. Objective life tends to awaken man's mental faculties, causing him to think and to reason; but it does not necessarily stir his deepest feelings. People who have lost their hearing and who no longer hear the harmonies of sound, usually become irritable, while people who have lost the power to see and yet have retained their hearing, are usually both gentle and kind in their natures. I do not mean to say that there are not exceptions to this rule, because one may have lost the outer hearing and have kept the sense of the inner, and have all the sweetness and gentleness that is to be found among the blind. We might mention as an illustration of this inner hearing that Beethoven, while of a somewhat irritable temperament, which was not improved by the loss of hearing, nevertheless was able to. hear with his inner ear, and produced more of his beautiful and remarkable music after he had practically lost the use of his outer hearing. Dr. Nicholas Saunderson, who lived in the early part of the last century, although blind, was one of the most celebrated mathematicians of his time, and he said: "Persons who are deprived of sight are generally blessed with a fine ear. Hence, perhaps it arises that music is a favourite study with the blind." "The doctor was a singular instance of this delicacy of ear. He could readily distinguish to the fifth part of a note, and by his performance on the flute, which he had learned as an amusement in his younger years, discovered a genius for music that would probably have appeared as wonderful as his excellence in mathematics, had he cultivated the art with equal application." In the development, then, of the mind and body, through the use of music and colour, one must take into account how colour affects the mind, and how hearing affects the emotions; and it will be through the union of both that the greatest development will come both to mind and body.
Very often doctors recommend a change of scene to patients who are not improving under their care, advising them to go to different places in the hope that their health may be restored. Now, if a change of scene is oftentimes necessary to restore health, how much greater must be the result arising from a harmony of sounds coming in touch with and arousing one's inmost feelings! For feeling is the dynamic that moves all life. We are what we are far more because of what we have felt than because of what we have thought. It is through our deepest feeling that we come into vital touch with God and man.
I have elsewhere stated that the body of man, when in a state of harmonious vibration, is also in a state of perfect health and strength. This physical vibration is, without doubt, dependent on harmonious thoughts and feelings; therefore, that which produces the greatest harmony of mind and feeling must, of a necessity, be the greatest agent not only in restoring mental poise and physical health, but also in keeping a person harmoniously balanced. But vibration may be either a means of building up or of destroying. The story told in the Old Testament about Joshua and his chosen followers marching seven times around a walled city, each one of the number blowing a trumpet, brings out the thought that it was through the united, rhythmic vibration of all the trumpets blown in unison that the walls were overthrown. The people who believe in the infallibility of Bible records look upon the overthrowing of the walls of Jericho as nothing short of a miracle; while people who do not accept the letter of either the Old or the New Testament, look upon it rather in the nature of a Hebrew myth. I feel quite sure that some time in the near future science will demonstrate the possibility of an entirely different theory.