But the human face and eyes flush at times with a radiance which might well be taken for a direct spiritual emanation entirely independent of ‘brute matter.’ Let us examine this point a little. Musical instruments, and also the human voice, have a peculiarity as regards their sounds which differs from mere pitch. A clarionet and a violin, for example, may be both pitched to the same note, but a listener who sees neither can at once tell that the _qualities_ of the notes are different. This difference is what the French call _timbre_, and the Germans, we believe, _Klang_. So, also, we can distinguish one vowel from another, though all may have the same pitch. The difference here, according to the recent investigations of Helmholtz, is due to the fact that certain incidental notes commingle in each case with the principal one, and produce a composite result. The ‘harmonics’ of a string are known to be due to minor vibrations which superpose themselves upon the principal ones, as small ripples cover parasitically the surfaces of large sea-waves. The notes of the true simple wave and of its parasites are heard at once, and it is the variation of the latter which produces differences in the _timbre_ of a musical instrument or of the human voice. In speculating on those more subtle phases of expression to which we have above referred, might we not offer the conjecture that they are not due to those waves alone which make the eyes violet or give the cheek its rose, but are a result produced by the compounding of these with incidental waves, which influence the colour as the harmonic waves of sound influence the pure quality of a note? We have often watched with deep interest and sympathy the countenances of some of the praying women in the churches of the Continent. We have seen a penitent kneeling at a distance from the shrine of the Virgin, as if afraid to come nearer. Suddenly a glow has overspread her countenance, strengthening in radiance, till at length her very soul seemed shining through her features. Sure of her acceptance, she has confidently advanced, fallen prostrate immediately in front of the image, and remained therefor a time in silent ecstasy. We have watched the ebbing of the spiritual tide, and remarked the felicitous repose which it left behind. At each new phase of emotion the _timbre_ of this woman’s countenance changed, and The music breathing from her face became altered in quality.