Śatapatha Brāhmaṇa ("of a hundred paths") 4.4.3.8

4.4.3.8

tasyonnetāśrāvayati | atirikto vā unnetā na hyeṣī 'nyasyāśrāvayatyatirikta eṣa grahastadatirikta evaitadatiriktaṃ dadhāti tasmādunnetāśrāvayati

For this (libation) the Unnetri calls for the Sraushat;--for the Unnetri is in excess (additional), since he does not call for the Sraushat for any other (libation); and this libation also is in excess: thus he puts the excess to the excess,--therefore the Unnetri calls for the Sraushat.