E.C. Marchant, Commentary on Thucydides Book 1

[4] 19. ναυμαχίας—defining gen; ἁλίσκονται of course is pres. for fut., ‘they are lost.’ (Some see here a reference after the event to the battle of Aegospotami and the capture of Athens; but the τε shows that the sentence is a conclusion from what precedes; and Aegospotami was not the result of the cause there stated.)

εἰ δ᾽ ἀντίσχοιεν—supposing they should hold out, i.e. if they are not defeated at sea after all (meaning suppose we are defeated instead), we shall get the better of them in the end.

24. δ δ᾽ ἐ. ἐπιστήμῃ προύχουσι—the advantage that they have in point of skill. ὅ is aceus. of measure, and the dat. as usual gives the point of excellence (ὅ is not accus, of respect; and as to Antig. 208 τιμὴν προέξους᾿ see Jehb's note). For the superiority of φύσις over διδαχή see c. 139. 2.

25. καθαιρετόν—we can annul: καθαιρετέον would mean we must, which does not give a good antithesis to οὐκ ἃν γένοιτο. Again C alone has the correct form.