Movement I - Measures 22 to 30

Measure 22 begins the secondary theme. The literal transcription is straightforward. 

But Beethoven, as usual, is not content with a literal transcription. In the the piano version, the accompaniment offers a contrast to the melody. It consists of chords on the strong beats against the syncopated melody.

In the string version, the accompaniment serves more as a complement to the melody. The lower strings play a counter-melody in thirds beginning on the first beat of measure 25 and moving in contrary motion with the first violin. At the end of the measure, the second violin joins the first violin in thirds.

Thirds or sixths in contrary motion produce a smooth, gentle sound in strings. Mozart used this technique to good effect in the opening of his Clarinet Quintet:

This change, therefore, emphasizes the contrast between the rising staccato line that begins the phrase and the legato cadence. This contrast is present in the original version, but it is less apparent. The string version brings the contrast into higher relief. After hearing this version, I'm sure that, when I play this sonata, I will play this passage differently.

Beethoven continues to follow his practice of articulating the downbeats more clearly in the string version. He replaces the half notes in measure 26 with quarter-note staccatos, and he eliminates the tie in the melody. Of course, this change is more subtle on the violin than it would be on the piano. There is a big difference between having the hammer strike the string again and simply changing direction of the bow. So the effect of repeating the G, especially when combined with retaining the tie in the second violin part, is simply to give an extra pulse to the downbeat. When the phrase repeats, however, Beethoven is not content with this extra pulse. In measure 30, he emphasizes the re-articulated F by adding a turn.