The Upanishads, Part 2 (SBE15), by Max Müller, , at sacred-texts.com
p. 70 p. 71 p. 72 p. 73
1. Verily 2 the dawn is the head of the horse which is fit for sacrifice, the sun its eye, the wind its breath, the mouth the Vaisvânara 3 fire, the year the body of the sacrificial horse. Heaven is the back, the sky the belly, the earth the chest 4, the quarters the two sides, the intermediate quarters the ribs, the members the seasons, the joints the months and half-months, the feet days and nights, the bones the stars, the
flesh the clouds. The half-digested food is the sand, the rivers the bowels 1, the liver and the lungs 2 the mountains, the hairs the herbs and trees. As the sun rises, it is the forepart, as it sets, the hindpart of the horse. When the horse shakes itself 3, then it lightens; when it kicks, it thunders; when it makes water, it rains; voice 4 is its voice.
2. Verily Day arose after the horse as the (golden) vessel 5, called Mahiman (greatness), which (at the sacrifice) is placed before the horse. Its place is in the Eastern sea. The Night arose after the horse as the (silver) vessel, called Mahiman, which (at the sacrifice) is placed behind the horse. Its place is in the Western sea. Verily, these two vessels (or greatnesses) arose to be on each side of the horse.
As a racer he carried the Devas, as a stallion the Gandharvas, as a runner the Asuras, as a horse men. The sea is its kin, the sea is its birthplace.
73:1 It is the third Adhyâya of the Âranyaka, but the first of the Upanishad.
73:2 This Brâhmana is found in the Mâdhyandina text of the Satapatha, ed. Weber, X, 6, 4. Its object is there explained by the commentary to be the meditative worship of Virâg, as represented metaphorically in the members of the horse. Sâyana dispenses with its explanation, because, as part of the Brihadâranyaka-upanishad, according to the Kânva-sâkhâ, it had been enlarged on by the Vârttikakâra and explained.
73:3 Agni or fire, as pervading everything, as universally present in nature.
73:4 Pâgasya is doubtful. The commentator suggests pâd-asya, the place of the feet, i.e. the hoof The Greek Pēgasos, or ἵπποι πηλοί, throws no light on the word. The meaning of hoof would hardly be appropriate here, and I prefer chest on account of uras in I, 2, 3. Deussen (Vedânta, p. 8) translates, die Erde seiner Füsse Schemel; but we want some part of the horse.
74:1 Guda, being in the plural, is explained by nâdî, channel, and sirâh; for we ought to read sirâ or hirâgrahane for sirâ, p. 22, l. 16.
74:2 Klomânah is explained as a plurale tantum (nityam bahuvakanam ekasmin), and being described as a lump below the heart, on the opposite side of the liver, it is supposed to be the lungs.
74:3 'When it yawns.' Ânandagiri.
74:4 Voice is sometimes used as a personified power of thunder and other aerial sounds, and this is identified with the voice of the horse.
74:5 Two vessels, to hold the sacrificial libations, are placed at the Asvamedha before and behind the horse, the former made of gold, the latter made of silver. They are called Mahiman in the technical language of the ceremonial. The place in which these vessels are set, is called their yoni. Cf. Vâgas. Samhitâ XXIII, 2.