Institutio Oratoria

I would suggest that the ripe scholar, who says

ave

without the aspirate and with a long e (for it comes from avēre and uses calefacere and conservavisse in preference to the usual forms, [*]( For havĕ, calfacere, conservasse. ) should also add face, dice and the like to his vocabulary.

His way is the right way. Who doubts it? But there is an easier and more frequented path close by. There is, however, nothing which annoys me more than their habit not merely of inferring the nominative from the oblique cases, but of actually altering it. For instance in ebur and robur, the forms regularly used both in writing and speech by the best authors, these gentlemen change their second syllable to o, because their genitives are roboris and eboris, and because sulpur and guttur keep the u in the genitive. So too femur and iecur give rise to similar controversy.