YV 2.7i

The Agrayana, is speech, the eighth day is speech, and therefore on the eighth day the Agrayana is drawn; verily he draws it in its own abode. (The cup) for Indra and Vayu is breath, the ninth day is breath, and therefore on the ninth day (the cup) for Indra and Vayu. is drawn; verily he draws it in its own abode. In that [4] it completes the metres, it completes for the third time the sacrifice; in that (the cup) for Indra and Vayu is drawn on the next day, where they have seen the sacrifice, thence does he again employ it, and they revolve round their own metre. They go by a trackless way leaving the path who start with anything except (the cup) for Indra and Vayu. The tenth day is the end of the sacrifice, (the cup) for Indra and Vayu is drawn on the tenth day; verily having reached the end of the sacrifice [5], they proceed from the trackless way to the path, and it is as when men go pushing on with a strong (team). The metres set their wishes on one another's world, and the gods then interchanged them. The fourth day is the abode of (the cup) for Indra and Vayu, the Agrayana is drawn on this (day); therefore (the cup) for Indra and Vayu is drawn on the ninth day, the abode of the Agrayana. The fifth day is the abode of the Çukra [6], (the cup) for Indra and Vayu is drawn on this (day); therefore the Çukra is drawn on the seventh day, the abode of (the cup) for Indra and Vayu. The sixth day is the abode of the Agrayana, the Çukra is drawn on this (day); therefore the Agrayana is drawn on the eighth day, the abode of the Çukra. Verily thus does he exchange the metres, and he who knows thus obtains interchange with the richer; verily also he causes concord in the sacrifice for the gods. Therefore one gives this to another. Prajapati desired, 'May I be propagated.' He saw this (rite) of twelve nights; he grasped it, and sacrificed with it. Then indeed was he propagated.