sounding point are all essential in getting the desired harmonic to sound. And to add to the challenge, in passages with different notes played as false harmonics, the distance between stopping finger and harmonic finger must constantly change, since the spacing between notes changes along the length of the string. The harmonic finger can also touch at a major third above the pressed note (the fifth harmonic), or a fifth higher (a third harmonic). These harmonics are less commonly used; in the case of the major third, both the stopped note and touched note must be played slightly sharp otherwise the harmonic does not speak as readily. In the case of the fifth, the stretch is greater than is comfortable for many violinists. In the general repertoire fractions smaller than a sixth are not used. However, divisions up to an eighth are sometimes used and, given a good instrument and a skilled player, divisions as small as a twelfth are possible. There are a few books dedicated solely to the study of violin harmonics. Two comprehensive works are Henryk Heller's seven-volume Theory of Harmonics, published by Simrock in 1928, and Michelangelo Abbado's five-volume Tecnica dei suoni armonici published by Ricordi in 1934. Elaborate passages in artificial harmonics can be found in virtuoso violin literature, especially of the 19th and early 20th centuries. Two notable examples of this are an entire section of Vittorio Monti's Csárdás and a passage towards the middle of the third movement of Pyotr Ilyich Tchaikovsky's Violin Concerto. A section of the third movement of Paganini's Violin Concerto No. 1 consists of double-stopped thirds in harmonics. When strings are worn, dirty and old, the harmonics may no longer be accurate in pitch. For this reason, violinists change their strings regularly. Right hand and tone color The strings may be sounded by drawing the hair of the bow held by the right hand across them (arco) or by plucking them (pizzicato) most often with the right hand. In some cases, the violinist will pluck strings with the left hand. This is done to facilitate transitions from pizzicato to arco playing. It is also used in some virtuoso showpieces. Left hand pizzicato is usually done on open strings. Pizzicato is used on all of the violin family instruments; however, the systematic study of advanced pizzicato techniques is most developed in jazz bass, a style in which the instrument is