To the external aids to expression belongs the swelling of the tones, one of the easiest, most natural, and most graceful of all our helps. It consists in giving a tone, whose time permits it, different degrees of strength. In a contrary way much time is usually spent in singing the scales, beginning _piano_ and increasing in strength to the greatest possible _forte_, and then letting the voice grow weaker and weaker. Instead of these exercises, which require exertion, the same thing can be attained far more easily by swelling the tones where it is required in the composition. In melancholy or mournful compositions, swelling upon those tones which the rhythm requires to be accented is very beautiful. But when exaggerated, or where a fresh, cheerful character is to be preserved in the composition, this aid to expression easily renders the effect sentimental. Unhappily, our whole music is vitiated by this sickly sentimentalism, the perfect horror of every person of cultivated taste. In these later years the powerful reaction of German æsthetics has had favorable results in regard to instrumental music, but in the execution of vocal music this unhealthy fashion of singing still always commands great applause. This sickly sentimental style has also naturalized in singing a gross trick unfortunately very prevalent, the _tremolo_ of the notes. When, in rare cases, the greatest passion is to be expressed, to endeavor to deepen the expression by a trembling of the notes is all very well and fully to be justified, but in songs and arias, in which quiet and elevated sentiments are to be expressed, to tremble as if the whole soul were in an uproar, and not at all in a condition for quiet singing, is unnatural and offensive. A very beautiful aid to expression, but now only seldom heard, is the transition from one register to another on the same note. A note begins with tolerable strength, for example, _d_, with the action belonging to it of the chest register, and while it grows weaker it passes imperceptibly into the action of the falsetto tones. Or the reverse. A note of the chest register is begun with the action of the falsetto, and becoming stronger changes into the chest register to which it naturally belongs. Correctly employed, the most delightful effects may be produced in this way, especially by a male voice.