ἐν πέτροισι πέτρον ἐκτρίβων → by grinding stone against stones
compertus: a, um, v. comperio.compertus: ūs, m. comperio,I experience, personal knowledge (late Lat. and very rare): compertu evidentia, App. M. 1, p. 103 fin.>
compertus,¹² a, um, part., de comperio.
