Verse 9.4.4.13

sa saṃdhyorupaspṛśya | ene yajuṣī japati tathā dve yajuṣī trīnparidhīnanuvibhavato divo mūrdhāsi pṛthivyā nābhiriti dakṣiṇe viśvasya mūrdhannadhi tiṣṭhasi śrita ityuttare mūrdhavatībhyām mūrdhā hyasyaiṣo 'psumatībhyāmagneretadvaiśvānarasya stotraṃ yadyajñāyajñiyaṃ śāntirvā āpastasmādapsumatībhyām

Preview of English translation:

13. Having touched it (the fire) at the two joints, he mutters these two formulas,—thus two formulas equal in power three enclosing-sticks,—with (Vajasaneyi Samhita XVIII, 54), “The sky’s head thou art, the earth’s navel, [the essence of the waters and plants, the life of all, the ample refuge (?): homage be to the path!]” on the right, and with (55), “On the head of the All dost thou keep standing, [in the (aerial) ocean is thy heart, in the waters thy life: bestow water, send the water-store (cloud),—from the sky, from the cloud, from the air, from the earth, favour us with rain!]” on the left (joint),—thus with two (verses) containing (the word) “head,” for this, is indeed its head; and containing (the words) “in the waters”: that Yajnayajniya doubtless is Agni Vaishvanara’s chant of praise, and water is (a means of) appeasing,—therefore (he touches them) with two (verses) containing (the words)—“the waters.”

For a detailled translation, including proper diacritics and footnotes, go the full English translation.