A bright, triumphant fanfare for a festal day. The chant is easily identified. The meter changes from ¢ to ¢3 at the initial alleluia with the tenor and bass voices in blackened notes (a device in the CC always signifying a hemiola when in triple meter). Those voices are therefore notated in duple rather than triple meter at that spot.
Viri Galilaei, quid admiramini aspicientes in caelum? alleluia:
quem admodum vidistis eum ascendentem in caelum, ita veniet, alleluia, alleluia, alleluia.
Omnes gentes plaudite manibus: Jubilate Deo in voce exsultationis
Men of Galilee, why are you gazing in astonishment at the heavens? Alleluia.
Just as you have seen Him ascend into heaven, so, in like manner shall He return. Alleluia, alleluia, alleluia.
All people, clap your hands, shout unto God with a voice of exultation.