Page 13

Here, by the NB, the open string is bowed, and the stopped notes are played by pressing with the first finger and plucking with the fourth finger.

10.
THE FLAGEOLET PLAYING IN SIMPLE TONES
The advantages it provides have been highlighted in a few words in the introduction, and it can be asserted with certainty that Paganini acquired his eminent precision and purity on the violin predominantly through flageolet playing. He possesses an incredible skill in this technique, both in single and double tones, in slow movements and rapid passages, without a single tone failing him.

Apart from those advantages, certain passages can also be played with ease, which would otherwise be impossible without this technique, such as No. 1. Others become easy and secure as a result, as in No. 2.
No. 1. [example]
No. 2. [example]
Considering all that has been stated, it truly remains incomprehensible that flageolet playing has been so completely neglected in modern times, even though it cannot be denied that for some, the difficulty and a fear of the great effort required to produce these tones may have been the primary deterrents.
The matter, however, is not as difficult as many might imagine. Fundamentally, the difference between regular playing and the production of flageolet tones lies in this: for the former, the fingers press firmly, whereas for the latter, they rest lightly on the strings.

With double tones, however, the difficulties increase, as producing two tones often requires the use of all four fingers. A significant difference in fingering flageolet tones is that they must always be placed slightly higher than regular tones. This is because, with flageolet tones, the string is gently touched with the very tip of the finger, whereas with regular tones, the entire width of the finger and firm pressure increase the string tension.

Even this has its benefits, as the left hand learns to distinguish the finest nuances in fingering with great precision. This is particularly necessary when playing regular tones in the higher positions at the end of the fingerboard, near the bridge.