There are yet other precautions, relative especially to the orchestra, which the conductor may also take, to avoid certain defects in performance. The instruments of percussion, placed, as I have indicated, upon one of the last rows of the orchestra, have a tendency to modify the rhythm, and slacken the time. A series of strokes on the drum struck at regular intervals in a quick movement, like the following:—
will sometimes lead to the complete destruction of a fine rhythmical progression, by checking the onward bound of the rest of the orchestra, and destroying the unity. Almost always, the drum player, through not observing the original time given by the conductor, is somewhat behindhand in striking his first stroke. This retardment, multiplied by the number of strokes which follow the first one, soon produces—as may be imagined—a rhythmical discrepancy of the most fatal effect. The conductor,—all whose efforts to re-establish unanimity are then in vain—has only one thing left to do; which is, to insist that the long drum player shall count beforehand the number of strokes to be given in the passage in question, and that, knowing his part, he shall no longer look at his copy, but keep his eyes constantly fixed upon the conducting-stick; by which means he will follow the time without the slightest want of precision.
Another retardment, arising from a different cause, frequently takes place in the trumpet-parts; it is when they contain a quick flow of passages such as this:—
The trumpet-player, instead of taking breath before the first of these three bars, takes breath at their commencement, during the quaver-rest, A; and, not counting for anything the short time it has taken him to breathe, gives its whole value to the quaver-rest, which thus becomes super-added to the value of the first bar. The result of this is the following:—
an effect all the worse because the final accent, struck at the commencement of the third bar by the rest of the orchestra, comes a third of the time too slow in the trumpets, and destroys unity in the striking of the last chord.
To obviate this, the conductor must first previously warn the players against such inexactness, into which they almost all are led to fall unawares; and then, while conducting, must cast a glance towards them at the decisive moment, and anticipate a little, by beating the first beat of the bar where they come in. It is incredible how difficult it is to prevent trumpet-players from doubling the value of a quaver-rest thus placed.
When a long accelerando, little by little, is indicated by the composer, for passing from an allegro moderato to a presto, the majority of orchestral conductors hurry the time by jerks, instead of quickening it equally throughout, by an insensible onward rate. This should be carefully avoided.