"To say that I was surprised at what Mr. Keely has discovered would be saying very little indeed ... It would appear that there are three different spheres in which the laws of motion operate. The first is the one in which Nature plays her grand fugue on the silent harp of Pendulums. In one period of Nature's grand fugue, as illustrated by pendulums, there are 19 ratios in 25 circles of oscillations ranging over 6 octaves; but all in silence. In the second sphere the tension of strings and other elastic bodies imbues them with forces operating upon the elastic air, producing vibrations quick enough to awaken sounds for the human ear. Here Nature plays on her tuneful harp the same grand fugue; from which everything in music is derived. In the third sphere, vibrating things, molecules, atoms, etc. gaseous, liquid, or solid have tensions and forces far beyond the requirements of music, and far above the audible region where musical sounds have been located by the Great Numberer. The multiplication of forces there, and their augmentation derived from sympathy, of which sympathy we have faint illustrations in the region of musical vibrations in both acute and grave harmonics, generate a concentration of mighty action, an ever-outgoing of Nature's own power, so that she, by her own laws of vibratory motion, can reproduce and perpetually maintain outgoing power of action; and, again, play in perfect harmony her grand fugue with these tremendous all-resolving forces in that high and hidden and silent region in which Mr. Keely is experimenting.
"The sympathy of one thing with another, and of one part of a thing with another part of it, arises from the principle of unity. For example, a string requires to be uniform and homogenous to have harmonics producing a fine quality of tone by the sweet blendings of sympathy; if it be not so, the tone may be miserable ... You say you wish I were in touch with Mr. Keely; so do I myself ... I look upon numbers very much as being the language which tells out the doings of Nature. Mr. Keely begins with sounds, whose vibrations can be known and registered. I presume that the laws of ratio, position, duality, and continuity, all the laws which go to mould the plastic air by elastic bodies into the sweetness of music, as we find them operative in the low silence of oscillating pendulums, will also be found ruling and determining all in the high silence of interior vibrations which hold together or shake asunder the combinations which we call atoms and ultimate elements, but which may really be buildings of wondrous complexity occupying different ranges of place and purpose between the visible cosmos and Him who built and evermore buildeth all things. The same laws, though operating in different spheres, make the likenesses of things in motion greater than the differences.
"MacVicar and Keely agree in the cosmical law being that of sympathetic association, or, under MacVicar's select name for it, assimilation, the watch-word and the law of Creation." from [Scientific Basis and Build of Music, page 86]