Closely connected with the desire for a periodic style is the tendency to frequent use of verbal antithesis, an artistic figure which provides a happy means of completing the period and the sense. It is useful because the second part of the antithesis supplies the reader or hearer with something which he is already expecting. It is the application in practice of a familiar psychological law of association by contrary ideas. Such contrast is emphasized in Greek by the common use of the particles μέν and δέ, and is of unnecessarily frequent occurrence in Athenian writers. All readers of Thucydides will remember that author’s craving for the contrast between ‘word and deed.’ In judicial rhetoric this kind of opposition must inevitably occur very often. From the nature of things each speaker will want to insist on his own honesty and the dishonesty of his opponents; the truth which he is telling as opposed to their lies, and to contrast the appearances, which seem so black against him, with the transparent whiteness of his character as revealed by a true account of the case. But Antiphon, like the speakers in Thucydides, carries this use of antithesis too far, for a sentence which contains too many contrasted ideas is difficult to follow, and so loses force. A fair example may be taken from the third speech of the second tetralogy: ‘I, who have done nothing wrong, but have suffered grievously and cruelly already, and now suffer still more cruelly not from the words but the acts of my adversary, throw myself upon your mercy, Gentlemen—you who are avengers of impiety but discriminators of piety—and implore you, in view of plain facts, not to be over-persuaded by a malicious precision of speech, and so consider the true explanation of the deed to be false; for his statement has been made with more plausibility than truth; mine will be made without guile, though at the same time without force.’ This outburst is part of a sentence in which the prosecutor expresses his indignation that the opponent whom he has accused of murder has had the audacity to defend himself at some length. One more example—from the speech on the charge of poisoning—is almost ridiculous. ‘Those whose duty it was to play the part of avengers of the dead and my helpers, have played the part of murderers of the dead, and established themselves as my adversaries.’ § 5 All speakers must consider the sound of their sentences as well as their grammatical structure, and among all careful writers we find that attention is paid to the balance of clauses. Some orators go further than this; they emphasize contrasts or parallels by the repetition of similar sounds and even show a preference for certain rhythms, it being a maxim of late rhetoricians that prose, though not strictly metrical in the same way as verse, should possess a characteristic rhythm of its own.