Another interesting fact is that the Chinese had ascertained the geometrical relation of musical pipes. The problem had been thoroughly examined by a certain Prince Tsai-Yu (1596). In practical and scientific hydrodynamics, the relation of the diameters of pipes to the volume contained was well known; but it appears that, as applied to sounding pipes, the Prince Tsai-Yu was the first clearly to record its demonstration. Of two musical pipes of the same diameter, one two feet long and the other one foot long, the latter does not, as assumed, give a note the higher octave of the former, for the note will be flat. Neither if we halve the diameter, even as we halve the length, will the note prove true. The common practice with us in organ building is to give the half diameter to the seventeenth pipe; but this is merely an empirical decision. The prince, without explaining theoretically why, showed that the proper dimensions relatively of length and diameter were as follows. Assuming a pipe of 2ft. length to have an interior diameter of 5 lines, then correctly the pipe of 1ft. length should have a diameter of 3 lines 53 cent., and a pipe of 6in. length a diameter of 2 lines 50 cent. Our organ pipe custom is solely a determination of ear, or feeling, as regards the aggregate of sounds; for we gain in brightness and fluency by not delaying the acceptance of the half diameter until the second octave, which geometrically would be its true position,—viz., at the twenty-fifth note. Thus, and by holding control in regard to the amount of wind, and regulating by voicing, we are able to blend the total accord of sounds in harmony, in the way pleasurable to the trained ear or cultivated taste, according to the perceptivities of the Western peoples. CHAPTER XV. In the Flowery Kingdom. THE BIRD’S NEST. Music by inspiration. Yes, that is it,—the very thing we want, what we are all longing for; so little of the truly inspired music comes newly to refresh us as the birth of the days we live in. Only the old seems the ever new. How inspiring it is to listen to the themes of the old masters, and feel the old melodies pass through us like a current of life, awakening thrills of delight, the memory of the first hearing of them blending with and enhancing the emotions of the present. To inspire, “to drink in.” How we drink in the life renewing melodies of Beethoven and Schubert: their potency never fails, and in our exultation we call them divine. How strangely inevitable are the ideas we associate with the words “divine” and “inspiration.” Apply them as we will to frail human effluences, there is no escape from the higher exalted sense, from the ideal signification. Inspiration,—it is a grand word. Somehow the ideal clings around words, in however “matter o’ fact” way they come to be used; like the eastern vase that has been filled with roses, in after time “The scent of the roses will cling round it still.”