Dawes' Canon.—The rule formulated by Dawes and afterwards extended (that the first aorist subjunctive active and middle after ὅπως, ὅπως μή, and οὐ μή is incorrect and should be emended) is applicable only in the case of verbs of effort. After these verbs the future is far more common than subjunctive or optative (except in Xenophon), and some scholars would emend the offending sigmatic subjunctives where they occur in the same sentence with second aorists (as 3.14) or even where the future has a widely different form (as ἐκπλευσεῖται, subj. ἐκπλεύσῃ, cp. A. 5.6.21).