Verse 10.5.4.8

tasyai vā etasyai ṣaṭtriṃśadakṣarāyai bṛhatyai yāni daśa prathamānyakṣarāṇi sā daśākṣaraikapadātha yāni viṃśatiḥ sā viṃśatyakṣarā dvipadātha yāni triṃśatsā triṃśadakṣarā virāḍatha yāni trayastriṃśatsā trayastriṃśadakṣarātha yāni catustriṃśatsā catustriṃśadakṣarā svarāḍatha yatsarvaiścandobhirayamagniścitastadaticandāstā u sarvā iṣṭakā eveṣṭaketi trīṇyakṣarāṇi tripadā gāyatrī tenaiṣa gāyatro'gnirmṛdāpa iti trīṇyakṣarāṇi tripadā gāyatrī teno evaiṣa gāyatro'tha yadantarā candasī tatsūdadohā atha yaccandaḥsvannaṃ tatpurīṣaṃ tā āhutayastāḥ samidho'tha yaccandāṃsītyākhyāyate tallokampṛṇā tadvā etatsarvaṃ candāṃsītyevākhyāyate tatsarvo'gnirlo

Preview of English translation:

8. Now the first ten syllables of this Brihati, consisting of thirty-six syllables, make an Ekapada of ten syllables; and the (first) twenty make a Dvipada of twenty syllables; and the (first) thirty a Viraj of thirty syllables; and the (first) thirty-three a (Viraj) of thirty-three syllables; and the (first) thirty-four a Svaraj of thirty-four syllables; and in that this fire-altar is built with all metres thereby it is an Atichandas, and (so) indeed are all these bricks. And the three syllables 'ishtaka (brick)' are a Gayatri tripada, whence this Agni is Gayatra; and the three syllables 'mrid' (clay) and 'apah' (water) also are a Gayatri tripada: thereby also he is Gayatra. And what is between (each two) metres is the Sudadohas; and the food which is in the metres is the earth-fillings, the oblations, and the fire-logs; and what is called 'metres,' that is the space-filling (brick):—thus this comes to make up the whole Agni; and the whole Agni comes to be the space-filler; and, verily, whosoever knows this, comes to be that whole (Agni) who is the space-filler.

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