Sul Ponticello.
A style of bowing which seems to be either very little understood, or very much neglected, is "sul ponticello" bowing. In string quartets, orchestral music, etc., a very fine effect is possible if all the players execute it in a proper manner. The bow should be drawn quite close to the bridge, with only medium pressure applied, the stroke should be performed more rapidly than ordinary bowing. This bowing executed by a number of strings gives a very weird effect, the only objection to its use being that if great skill is not used, the string, instead of vibrating as a whole, will vibrate in segments, thus giving out one or other of the natural harmonics. It is stated that Paganini used to play certain passages in harmonics after the above manner; harmonic tones may be produced on any stopped note, by the bow alone, as follows. The bow should be drawn very lightly across the strings near the bridge, the left hand fingers firmly stopping the notes; various harmonics may be produced with one fingering by slightly varying the position of the bow, moving it slightly nearer or away from the bridge. Except for special passages, which are really intended for this kind of ponticello harmonic playing, it is not advisable to introduce it; the slightest irregularity in the position of the bow on the string will alter the harmonic notes to a great extent.