Śatapatha Brāhmaṇa ("of a hundred paths") 1.2.2.4

1.2.2.4

atha dvedhā karoti | yadi dve haviṣī bhavataḥ paurṇamāsyāṃ vai dve haviṣī bhavataḥ sa yatra punarna saṃhaviṣyaṃtsyāttadabhimṛśatīdamagneridamagnīṣomayoriti nānā vā etadagre havirgṛhṇanti tatsahāvaghnanti tatsaha piṃṣanti tatpunarnānā karoti tasmādevamabhimṛśatyadhivṛṇaktyevaiṣa puroḍāśamadhiśrayatyasāvājyam

He now divides it into two halves, if there be two oblations: at the full-moon sacrifice there really are two oblations. He then touches them,--where (by so doing) he would not again mix (the two) together,--with the (respective) formulas (Vâg. S. I, 22): 'This to Agni!' 'This to Agni-Soma!' Separately indeed they take that sacrificial food (from the cart) in the first place; then they thresh it together, then they grind it together, then he again divides it: for this reason he thus touches (them separately). The one (the Adhvaryu) now places the cake over (the fire), the other (the Âgnîdhra) puts the clarified butter on: