Only on the last night of Atalanta did I notice the viola part in the aria ‘Lassa, ch’io t’ho perduta’. The bass line is the fundament literally and figuratively of Baroque music, of course (and both Bach and Handel remove it to great effect in some of their arias), and in this aria the bass line is sometimes flowing quavers and sometimes on-the-beat crochets. This contrasts with the violins (in unison), which are off the beat, giving the aria the breathless quality of a heart missing its beat: Atalanta has been suddenly thrown from her orbit by falling in love with Tirsi. If the violins are her irregular heart, the violas are her soul. This line is, like the bass, on the beat. But it is not an amplification or accompaniment to the bass. The viola part consists mainly of a four-note phrase which starts always on the dominant and alternates with the sung line, so that there is little overlap, unlike the violin and bass lines. The exception is bars 49-54, when violin II splits away from violin I and joins the viola and Atalanta with a crochet-crochet-rest sighing, enveloped by the dotted minims of the first violin and bass line.
Oh, gosh, it’s gorgeous. The use of the viola here reminds me slightly of Bach’s ‘Er kennt die rechten Freudenstunden’ from ‘Wer nur den Lieben Gott lässt walten’ (Cantata 93), where the violas carry the chorale through a running duet (see here.) I shall now start really looking at Handel and the viola.