It is enhanced—­to take a last point—­by the use of a literary expedient.  Not even in Richard III., which in this, as in other respects, has resemblances to Macbeth, is there so much of Irony.  I do not refer to irony in the ordinary sense; to speeches, for example, where the speaker is intentionally ironical, like that of Lennox in III. vi.  I refer to irony on the part of the author himself, to ironical juxtapositions of persons and events, and especially to the ’Sophoclean irony’ by which a speaker is made to use words bearing to the audience, in addition to his own meaning, a further and ominous sense, hidden from himself and, usually, from the other persons on the stage.  The very first words uttered by Macbeth,

     So foul and fair a day I have not seen,

are an example to which attention has often been drawn; for they startle the reader by recalling the words of the Witches in the first scene,

Fair is foul, and foul is fair.

When Macbeth, emerging from his murderous reverie, turns to the nobles saying, ‘Let us toward the King,’ his words are innocent, but to the reader have a double meaning.  Duncan’s comment on the treachery of Cawdor,

                       There’s no art
     To find the mind’s construction in the face: 
     He was a gentleman on whom I built
     An absolute trust,

is interrupted[198] by the entrance of the traitor Macbeth, who is greeted with effusive gratitude and a like ‘absolute trust.’  I have already referred to the ironical effect of the beautiful lines in which Duncan and Banquo describe the castle they are about to enter.  To the reader Lady Macbeth’s light words,

     A little water clears us of this deed: 
     How easy is it then,

summon up the picture of the sleep-walking scene.  The idea of the Porter’s speech, in which he imagines himself the keeper of hell-gate, shows the same irony.  So does the contrast between the obvious and the hidden meanings of the apparitions of the armed head, the bloody child, and the child with the tree in his hand.  It would be easy to add further examples.  Perhaps the most striking is the answer which Banquo, as he rides away, never to return alive, gives to Macbeth’s reminder, ’Fail not our feast.’  ‘My lord, I will not,’ he replies, and he keeps his promise.  It cannot be by accident that Shakespeare so frequently in this play uses a device which contributes to excite the vague fear of hidden forces operating on minds unconscious of their influence.[199]

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