"Dr. Wollaston constructed a small organ, whose notes began where the notes of ordinary instruments end; the notes of his organ increased in sharpness till they became inaudible, though he was certain that it continued to give sound, from feeling the vibrations equally with the lower notes. He thus found that some people could hear seven or eight notes higher than others, and that children could generally hear two or three notes higher than grown-up people. In some persons, the accuracy of the ear is merely impaired in distinguishing faint sounds, and sounds somewhat similar; instances of this kind are particularly evident in infants, whose first attempts at speech are a very remote similarity to the sounds they hear, and become more perfect as their ear is educated, and in some cases remain imperfect through life, in consequence of defect in the organs of hearing. All imperfections of speech do not arise from imperfect hearing; an indistinct articulation may result from various other causes; from carelessness, from defective organs of speech, or from an imperfect formation of those organs; from irregular respiration, producing hesitation, and in some instances proceeding from nervousness."[34] [34] See Dr. Arnott's "Elements of Physics," 1827. The writer is acquainted with a lady, whose organs of hearing are in full activity, but she cannot distinguish one tune from another; her ear appreciates _piano_, _forte_, or _fortissime_, but neither modulation nor rhythm. The defect here must be in the mind, (a phrenologist would say that the organ of music in the brain was undeveloped,) yet this lady is sensible, pious, and strenuous in her exertions for the extension of the knowledge of Christ.