Contraction.—If either of the syllables to be contracted had an accent, the contracted syllable has an accent. Thus:
a. A contracted antepenult has the acute: φιλεόμενος φιλούμενος.
b. A contracted penult has the circumflex when the ultima is short; the acute, when the ultima is long: φιλέουσι φιλοῦσι, φιλεόντων φιλούντων.
c. A contracted ultima has the acute when the uncontracted form was oxytone: ἑσταώς ἑστώς; otherwise, the circumflex: φιλέω φιλῶ.
N. 1.—A contracted syllable has the circumflex only when, in the uncontracted form, an acute was
If neither of the syllables to be contracted had an accent, the contracted syllable has no accent: φίλεε φίλει, γένεϊ γένει, περίπλοος περίπλους. For exceptions, see cross236 b.173
Crasis.—In crasis, the first word (as less important) loses its accent: τἀ_γαθά for τὰ ἀγαθά, τἀ_ν for τὰ ἐν, κἀ_γώ for καὶ ἐγώ.
a. If the second word is a dissyllabic paroxytone with short ultima, it is uncertain whether, in crasis, the paroxytone remains or changes to properispomenon. In this book τοὔργον, τἄ_λλα are written for τὸ ἔργον, τὰ ἄλλα; but many scholars write τοὖργον, τἆλλα.174
Elision.—In elision, oxytone prepositions and conjunctions lose their accent: παρ' (for παρὰ) ἐμοῦ, ἀλλ' (for ἀλλὰ) ἐγώ. In other oxytones the accent is thrown back to the penult: πόλλ' (for πολλὰ) ἔπαθον.
a. Observe that in πόλλ' ἔπαθον the acute is not changed to the grave ( cross154 a, cross3). A circumflex does not result from the recession of the accent. Thus, φήμ' (not φῆμ') ἐγώ for φημὶ ἐγώ. τινά and ποτέ, after a word which cannot receive their accent ( cross183 d), drop their accent: οὕτω ποτ' ἦν.
a. When the preposition follows its case: τούτων πἐρι (for περὶ τούτων)
N. 1.—In poetry anastrophe occurs with the other dissyllabic prepositions (except ἀντί, ἀμφί, διά). In Homer a preposition following its verb and separated from it by tmesis ( cross1650) also admits anastrophe (λούσῃ ἄπο for ἀπολούσῃ).
N. 2.—When the final vowel of the preposition is elided, the accent is dropped if no mark of punctuation intervenes: χερσὶν ὑφ' ἡμετέρῃσιν B 374.
b. When a preposition stands for a compound formed of the preposition and ἐστί. Thus, πάρα for πάρεστι
N.—In poetry, πάρα may stand for πάρεισι or πάρειμι; and ἄνα
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].