This topick, which has been always employed with too much success, is used in this scene, with peculiar propriety, to a soldier by a woman.  Courage is the distinguishing virtue of a soldier, and the reproach of cowardice cannot be borne by any man from a woman, without great impatience.

She then urges the oaths by which he had bound himself to murder Duncan, another art of sophistry by which men have sometimes deluded their consciences, and persuaded themselves that what would be criminal in others is virtuous in them:  this argument Shakespeare, whose plan obliged him to make Macbeth yield, has not confuted, though he might easily have shown that a former obligation could not be vacated by a latter.

NOTE XVII.

  Letting I dare not wait upon I would,
  Like the poor cat i’ th’ adage.

The adage alluded to is, The cat loves fish but dares not wet her foot.

Catus amat pisces, sed non vult tingere plantas.

NOTE XVIII.

  Will I with wine and wassel so convince.

To convince is, in Shakespeare, to overpower or subdue, as in this play: 

 —­Their malady convinces
  The great assay of art.

NOTE XIX.

 —­Who shall bear the guilt
  Of our great quell?

Quell is murder, manquellers being, in the old language, the term for which murderers is now used.

NOTE XX.

ACT II.  SCENE II.

 —­Now o’er one half the world
  (a)_Nature seems dead_, and wicked dreams abuse
  The curtain’d sleep; now witchcraft celebrates
  Pale Hecat’s offerings:  and wither’d murther,
  Alarum’d by his sentinel, the wolf,
  Whose howl’s his watch, thus with his stealthy pace,
  With (b)Tarquin’s ravishing sides tow’rds his design
  Moves like a ghost.—­Thou sound and firm-set earth,
  Hear not my steps, which way they walk, for fear
  Thy very stones prate of my where-about;
  And (c)take the present horror from the time,
  Which now suits with it.—­

(a)—­Now o’er one half the world
   Nature seems dead.

That is, over our hemisphere all action and motion seem to have ceased.  This image, which is, perhaps, the most striking that poetry can produce, has been adopted by Dryden, in his Conquest of Mexico.

  All things are hush’d as Nature’s self lay dead,
  The mountains seem to nod their drowsy head: 
  The little birds in dreams their songs repeat,
  And sleeping flowers beneath the night dews sweat. 
  Even lust and envy sleep!

These lines, though so well known, I have transcribed, that the contrast between them and this passage of Shakespeare may be more accurately observed.