The Grihya Sutras, Part 1 (SBE29), by Hermann Oldenberg, , at sacred-texts.com
1 1. If (in the chariot) of a king the axle breaks, or something that is bound loosens itself, or the chariot is overturned, or if another accident happens, or (if one of these same things occurs) when a bride is carried home, he establishes the same fire, prepares Âgya, and sacrifices (two Âgya oblations) separately with the two Mantras, 'Here is joy' (Vâg. Samh. VIII, 51 a).
2. Having got ready another chariot, he (i.e. the Purohita or the bridegroom) should make the king or the woman sit down thereon with (the formula), 'In royal power' down to the word, 'in sacrifice'
[paragraph continues] (Vâg. Samh. XX, 10), and with the (verse), 'I have seized thee' (ibid. XII, 11).
3. The two beasts that draw the chariot, constitute the sacrificial fee.
4. (This is) the penance.
5. Then (follows) feeding of the Brâhmanas.
287:1 10, 1. 'The same fire' is the senâgni (the fire belonging to the army) in the case of the king, the nuptial fire in the second case. The two Mantras are the two parts of Vâg. Samh. VIII, 51 a.