Shatapatha Brahmana 5.5.1.3

5.5.1.3

sa yadāgneyenāṣṭākapālena puroḍāśena pracarati | yadevainam prācīṃ diśaṃ samārohayati yadṛtūnyatstomānyaccandāṃsi tasmādevainametena niṣkrīṇāti saṃsravam bārhaspatye carāvavanayati

And why he proceeds with the cake on eight potsherds for Agni,--because he makes him ascend the eastern region, the seasons, the hymns and metres, he now redeems him therefrom by this (oblation). The remains of it he pours on the Brihaspati pap.