Georg Autenrieth, A Homeric Dictionary

εἰς, ἐς (εἰς before a consonant only in εἰσβαίνω): into.—I. adv. (the socalled ‘tmesis’), ἐς δ᾽ ἦλθον, ἐς δ̓ ἐρέτα_ς ἀγείρομεν, Il. 1.142; an acc. in the same clause may specify the relation of the adv., thus preparing the way for a true prepositional use, τὼ δ᾽ εἰς ἀμφοτέρω Διομήδεος ἅρματα (acc. of end of motion) βήτην, Θ 115, Od. 2.152. —II. prep. w. acc., into, to, for; ἐς ἀλλήλους δὲ ἴδοντο, ‘towards’ each other, into each other's faces, Il. 24.484; of purpose, εἰπεῖν εἰς ἀγαθόν, ‘for’ a good end, Il. 9.102 ; εἰς α?την, ‘to’ my ruin, Od. 12.372; of time, εἰς ἐνιαυτόν, i. e. up to the end of a year, Od. 4.595; so εἰς ὅ κε, until; distributively, αἰεὶ εἰς ὥρα_ς, ‘season after season’ (cf. in dies), Od. 9.135. Apparently w. gen., by an ellipsis, εἰς Ἀιδα_ο (sc. δόμον), ἐς Πριάμοιο, and by analogy, εἰς Αἰγύπτοιο (sc. υ?δωρ), εἰς ἡμετέρου, Od. 2.55, etc.