The Grihya Sutras, Part 1 (SBE29), by Hermann Oldenberg, , at sacred-texts.com
1 1. If (a strong) wind is blowing, and on the new-moon day there is an entire interruption of study.
2. If one has partaken of a Srâddha dinner, if a meteor falls, or distant thundering is heard, or if the earth quakes, or if fiery apparitions are seen, and when a new season begins, (the study shall be interrupted) until the same time next day.
3 3. If the Utsarga ceremony has been performed,
if clouds appear, . . . ., (it shall be interrupted) through a period of three nights or till twilight has thrice passed.
4 4. After he has eaten, until he has (washed and) dried his hands; while being in water; at nighttime; at the time of the morning and evening twilight; while a dead body or a Kandâla is in the village.
5. While running, while seeing a person of bad fame or who has lost his caste, if a miraculous or happy event happens, as long as (that which occasions the interruption of study) endures.
6. If hoar-frost (lies on the ground), if a musical instrument is heard, or the cry of a person in pain, at the border of the village, in a burial ground, or if a dog, an ass, an owl, a jackal, or a Sâman song is heard, or if a learned person approaches, as long as (that occasion) endures.
7. If his Guru has died, let him go down into water (for offering water-oblations) and interrupt (the study) for ten nights.
8 8. If one who has performed with him the Tânûnaptra ceremony, or a fellow-pupil (has died), for three nights.
9. If one who is not his fellow-pupil, (has died,) for one night.
10. After having studied five months and a half, they should celebrate the Utsarga,
11. Or six months and a half.
12 12. They then mutter this Rik: 'Ye two young sages! The relation which has expired among us, the friendship we dissolve, (turning away) from the condition of friendship.'
13. After having remained together through a period of three nights, they separate.
323:1 11, 1. 'Entire interruption' means, according to the commentators, that not only the study of the Veda itself, but also that of the Vedâṅgas, or even all sorts of worldly instruction are forbidden.
323:3 I have left the words sarvarûpe ka untranslated. Evidently p. 324 sarvarûpa is identical with the doubtful word savarûpa which twice occurs in the Sâṅkhâyana-Grihya. See the discussion on that word in the note on Sâṅkhâyana II, 12, 10.
324:4 On antardivâkîrtye, comp. Manu V, 85. Gautama XVI, 19.
324:8 The Tânûnaptra is an invocation directed to Tanûnaptri (i.e. the wind) by which the officiating priests and the Yagamâna at a Soma sacrifice pledge their faith to do no harm to each other. See Indische Studien, X, 362.
325:12 The reading of the Mantra is doubtful. I think it should stand as Professor Stenzler has printed it, except that I should propose to correct yuvâ into yuvânâ (comp. Âsvalâyana-Srauta VI, 12, 12). It is probable that the gods addressed are the two Asvins, who are called kavî and yuvânâ in several passages of the Vedas.