A syllable is long by position when its vowel precedes two consonants or a double consonant: ἵππος
a. One or both of the two consonants lengthening a final syllable by position may belong to the next word: ἄλλο_ς πολί_της, ἄλλο_ κτῆμα.
b. Length by position does not affect the natural quantity of a vowel. Thus, both λέ-ξω
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].