In a decrescendo the reverse action takes place. The bow is placed very firmly on the strings near the bridge, great pressure being applied. As the stroke proceeds the pressure is gradually withdrawn, the bow moves more slowly, and approaches the fingerboard.
The effect of Ex. 4 is a combination in one bow of the crescendo and decrescendo effects given in bowings 2 and 3. The bow must be used very sparingly at the crescendo, so that sufficient may be left to sustain a bold forte, for the middle of the semibreve, and also to allow the tone to be gradually diminished. The student cannot devote too much time to the study of this difficult bowing; if properly mastered, great command of the bow, in a slow bow-stroke, will have been obtained.
Scales played with two minims slurred (Ex. 5) should have whole smooth bow-strokes. In approaching an open string, care should be taken to prevent any break in the bow-stroke, or any roughness being perceptible. The open string should first be caused to vibrate with the friction of the bow, the pressure then being applied. Equal divisions of the bow are necessary for each minim, the bow being lightly placed at the heel, with slightly increasing pressure, as the point is neared; this is required to keep the tone-volume equal with that produced at the heel.
Four crotchets slurred, are to be played with the same kind of bowing as Ex. 5, but here there are four notes to one bow-stroke. Each crotchet should have its full time value allowed, and the stroke should be equally divided, so that each note gets about a fourth of the bow. Equality of tone, and smoothness are the chief characteristics of a good performance of this and all similar slurred bowings. There should not be the slightest break between each crotchet, one note only being left off as the next is sounded.
Smooth detached crotchets may be played with the upper half of the bow. In this style of detached bowing, each note must be approached and left without any roughness, a clear division of the notes being suggested rather than any decided break made. When moving from one position to another, no gliding is allowed, each note separate, but smooth.