[1] Melody in all its aspects.
These words of Wagner’s are excellent, but they may convey an exaggerated conception of the case to an amateur. It is beyond dispute that if the tempo is incorrect, the performance must inevitably be weak or utterly bad; but it does not follow that when the tempo is right, all will be satisfactory. Nevertheless, it is true that the first and most important duty of the conductor is to decide the tempo, and that he can only do by a complete comprehension of the musical character of the composition. In music written since Beethoven’s day the conductor has something to guide him in the matter of tempo, as I shall presently show; but in earlier compositions he will find only such general terms as allegro, adagio, or andante. He will not even discover such attempts at specification as andante con moto, allegro pesante, or presto ma non troppo.
These directions are not sufficiently precise. Wagner himself tells how he wrote “Mässig” (moderate) in the score of “Das Rheingold,” with the result that the drama took three hours under the opera conductor. “To match this,” he adds, “I have been informed that the overture to ‘Tannhäuser,’ which, when I conducted it at Dresden, used to last 12 minutes, now lasts 20.” Wagner notes that Sebastian Bach did not customarily indicate the tempo at all, “which in a truly musical sense is perhaps best.” But to leave all movements without tempo marks would be to assume that all conductors were truly gifted. Since Beethoven’s latter days it has been the custom of composers to indicate the correct tempo by what is known as the metronome mark.
A metronome is an instrument which can be set to tick off with a pendulum any number of beats from forty to two hundred and eight a minute. A composer desiring to indicate a tempo uses a formula like this: M. M.
= 78.
The letters M. M. mean Maelzel’s Metronome (the instrument). The note (in this case a minim) means that the beats of the pendulum are to be regarded as representing minims, crotchets, or quavers, as the case may be. The figure indicates the number of beats per minute. In the above formula the composition would probably be one written in two-fourth time, that is, with one minim to a bar, and the metronome mark would indicate that seventy-eight minims, and hence in this case seventy-eight bars, were to be played each minute.
A metronome mark must not be understood as requiring a rigid adherence to its prescription in every bar of a movement. It is simply a method of expressing the general rate of progress. A conductor could not count every bar by the metronome without abandoning all attempts at accelerandi or ritardandi, and generally reducing his performance to a mathematical state of rectangularity. All flexibility, elegance, and nuance would disappear from such a rendering.
For dance-music played at a ball, strict adherence to the metronome mark throughout a composition would be admissible; and it would be really desirable in the case of a military march, in which the tactics prescribe the cadence as one hundred and twenty steps a minute; but it is not to be tolerated in artistic concert music. The metronome mark establishes the general movement, and that is all.
Any music-lover who desires to find out the right tempo of a metronomed composition can do so by using a watch with a second hand. If he times the number of measures to be played in five or ten seconds, he can get at the tempo. Similarly, he can “hold the watch” on a conductor in the performance of any piece with an established tempo. Here again, however, he must beware of exaggerated accuracy.