The Upanishads, Part 1 (SBE01), by Max Müller, , at sacred-texts.com
1. Some say: 'Let him take a Gâyatrî hymn for the Pra-uga. Verily, Gâyatrî is brightness and glory of countenance, and thus the sacrificer becomes bright and glorious.'
2. Others say: 'Let him take a Ushnih hymn for the Pra-uga. Verily, Ushnih is life, and thus the sacrificer has a long life.'
Others say: 'Let him take an Anushtubh hymn
for the Pra-uga. Verily, Anushtubh is valour, and it serves for obtaining valour.'
Others say: 'Let him take a Brihatî hymn for the Pra-uga. Verily, Brihatî is fortune, and thus the sacrificer becomes fortunate.'
Others say: 'Let him take a Paṅkti hymn for the Pra-uga. Verily, Paṅkti is food, and thus the sacrificer becomes rich in food.'
Others say: 'Let him take a Trishtubh hymn for the Pra-uga. Verily, Trishtubh is strength, and thus the sacrificer becomes strong.'
Others say: 'Let him take a Gagatî hymn for the Pra-uga. Verily, cattle is Gagatî-like, and thus the sacrificer becomes rich in cattle.'
But we say: 'Let him take a Gâyatrî hymn only. Verily, Gâyatrî is Brahman, and that day (the mahâvrata) is (for the attainment of) Brahman. Thus he obtains Brahman by means of Brahman.
4. 'And it must be a Gâyatrî hymn by Madhukkhandas,
5. 'For Madhukkhandas is called Madhukkhandas, because he wishes (khandati) for honey (madhu) for the Rishis.
6. 'Now food verily is honey, all is honey, all desires are honey, and thus if he recites the hymn of Madhukkhandas, it serves for the attainment of all desires.
7. 'He who knows this, obtains all desires.'
This (Gâyatrî pra-uga), according to the one-day (ekâha) ceremonial 1, is perfect in form 2. On that day (the mahâvrata) much is done now and then which
has to be hidden 1, and has to be atoned for y recitation of hymns). Atonement (sânti) is rest, the one-day sacrifice. Therefore at the end of the year (on the last day but one of the sacrifice that lasts a whole year) the sacrificers rest on this atonement as their rest.
8. He who knows this rests firm, and they also for whom a Hotri priest who knows this, recites this hymn.
161:3 Thus far the hymn which has to be recited by the Hotri priest, after the eating of the ritugrabas, has been considered. What follows next is the so-called Pra-uga hymn, consisting of seven trikas, which the Hotri has to recite after the Visvedevagraha. Different Sâkhâs recommend hymns of different metres, our Sâkhâ fixes on the Gâyatrî.
162:1 It is copied from the Visvagit, and that from the Agnishtoma.
162:2 Nothing is wanting for its performance, if one only follows the rules given in the Agnishtoma.
163:1 Dâsînritya-bahubhûtamaithuna-brahmakâripumskalîsampravâ-dâdikam. See Rajendralal Mitra, Introduction to his edition of the Aitareya-âranyaka, p. 25. It might be better to join ekâhah with sântyâm, but even then the argumentation is not quite clear.