Vedic Metre in its Historical Development c12.s3.93

c12.s3.93

171. To complete the discussion above (§ 160) of the particle *ū u*, and as a preliminary to the study of the quantity of final long vowels before hiatus, it is necessary to investigate the relation of the endings -*āv* -*o* in the text of the Rigveda to final -*ā*, as well as the relation of the disyllabic ending -*ā u* to final -*ai*, -*au*, and *āḥ*. Final -*āv* regularly appears in place of a dual in -*ā* before hiatus (except before *u*-), even when the syllable is short. Final -*o* is of various origin: sometimes it must be resolved into -*a ū* or -*ā ū*, the latter element being the particle *ū* or *u*;