Those theorists who regard our diatonic major scale as the most perfect one, which ultimately must be universally accepted as the only true one, will probably not admit that under certain circumstances the sounding of one or other of its intervals a little "out of tune" may actually increase the beauty of a musical performance. Such is, however, unquestionably the case. To note a curious instance in proof of the correctness of this assertion as afforded by the clavichord, a contemporary of the harpsichord and predecessor of the pianoforte:--The strings of the clavichord are not sounded by being twanged with quills, as is the case in the harpsichord, but are vibrated by means of iron pins, called tangents, which press under the strings when the keys are struck. The pressure of the tangent lasts as long as the key to which the tangent is attached is held down. The deeper the performer presses the key down with his finger, the stronger is the pressure of the tangent against the string, and the more the string is raised by it. The raising of the string has the effect of slightly raising the pitch of its tone. The performer, therefore, has it in his power to modify in some degree the pitch of a tone, and by this means to distinguish any tone to which he desires to give emphasis, or to render prominent in expressing a melody, or in executing a passage with delicacy. The aptness of the clavichord for yielding to these deviations from the intonation of the intervals in which it is tuned, combined with its aptness for producing with great delicacy different degrees of loudness, constitute the principal charms of the instrument, and sufficiently account for the love which our old classical composers,--Handel, Bach, etc.,--bore for the clavichord.