Caprice no. 14 juxtaposes harmonization in thirds with florid melisma. These beautiful "aria" caprices seem to point toward the aria style that was developing in Italian opera. One of my listeners recently mentioned that this caprice reminded them of an aria from Verdi's Don Carlos.
Campagnoli seems to use the viola solo as a one-person show: I get to play my own curtain rise with the prelude (mm. 1-12), and a duet, starting at m.13. The voices are distinct enough that they could function on their own. Notice how they even break apart into a dialogue at m. 26, coming back together in the last measure for a satisfying resolution.