Book 1
6.2
Authority as a rule we derive from orators and historians. For poets, owing to the necessities of metre, are allowed a certain licence except in cases where they deliberately choose one of two expressions, when both are metrically possible, as for instance in imo de stirpe recisum and aeriae quo congessere palumbes or silice in nuda Aen. xii. 208: cutaway from the lowest root. Ecl. iii. 69: where airy doves have made their nest. Ecl. i. 15: on the naked rock. Stirps, palumbes and silex are usually masculine. and the like. The judgment of a supreme orator is placed on the same level as reason, and even error brings no disgrace, if it result from treading in the footsteps of such distinguished guides.
6.3
Usage however is the surest pilot in speaking, and we should treat language as currency minted with the public stamp. But in all these cases we have need of a critical judgment, especially as regards analogy (a Greek term for which a Latin equivalent has been found in proportion).
