Tempo rubato may be compared to speaking certain words more slowly or more rapidly in order that the essential meaning of the entire sentence may be more strongly impressed upon the listener. It must not however break up the continuity of the tempo; as one writer has said "we must bend the tempo, but not break it." Another well-known author, in treating the same point, states that[15]
Freedom in tempo does not mean unsteadiness.... We must have in music the sense of equilibrium, of stability. A careless, spasmodic hurrying and retarding leads only to flabbiness and inconsequence.
The most common kind of rubato is probably that in which the first part of the phrase (up to the climax) is accelerated, the climacteric tone lingered upon slightly, then the remainder of the phrase rendered a tempo or possibly slightly ritardando. But there are many phrases that demand a totally different sort of treatment; e.g., a ritardando in the first part instead of an accelerando. Which is the appropriate way of delivering any particular phrase must be determined in every case by musical feeling.
The thing that the beginner is apt to forget at the period when his musical feeling though sincere is yet characterized by lack of refinement, is that these nuances must always be subtle, and that the listener ought not to have fluctuations in tempo thrust in his face at every turn. Indeed we may say that he should hardly know that they are present, unless he is making a definite attempt to analyze the performance. The familiar story of Chopin's breathing toward a candle flame and making it flicker slightly, with the remark, "That is my rubato," then blowing it violently out and saying "This is yours," is quite to the point in this connection.
It is of course understood that rubato is to be employed almost exclusively in moderate or slow tempos, having little or no place in rapid, strongly rhythmic music. It should also be remarked that the more severe the form of the music,—the more architectonic it is—the less variation in tempo should there be in its rendition, for in this type of music the expression is primarily intellectual. Such instrumental works (of which certain compositions of Bach and Mozart are typical) must not be played sentimentally, as a modern English writer has remarked, and yet they must be played with sentiment. The remarks of this same author may well be quoted in closing this discussion:[16]
Rubato is necessary in emotional music and is an excellent means of picturing longing, persuading, dreaming, et cetera. That is why its use is so characteristic in performing the works of the romantic school and why it must be used with such caution in the classics. The classic must be clear as daylight—the structure must be evident even on the surface; but the romantic composition needs often to be played in a veiled manner in order to produce atmosphere. In such a case the rhythm is veiled as it were, draped in gauze, but the rhythmic design is there under the veil just the same. To express calmness, decision, et cetera, avoid rubato.
It must now be evident to the reader that this whole matter of musical nuance is too subtle to be treated adequately in a book of this character, and it becomes necessary for us once more to advise the amateur to study music, both vocal and instrumental, in order that his latent musical feeling may be developed into a ripe and adequate musical taste.
TEMPO RECORDED IN MUSCLES
In concluding the chapter let us emphasize the fact that the establishing of a tempo is a matter of muscle even more than of mind, and that before beginning to beat time the conductor should have the tempo recorded in his muscular memory. Before rising to conduct a composition then let him feel its tempo in the muscles of the arm and hand wielding the baton; for if not thus felt, the work will rarely be begun with a clearly defined rate of speed. This consideration receives added weight when it is recalled that if the conductor does not set the tempo, the chorus accompanist or first violinist will, and they, not having studied the music from this standpoint, will rarely succeed in hitting upon the correct rate of movement.