Speak, I charge you!

with the easily satisfied mind of the self-uninterested Banquo:—

The air hath bubbles, as the water has,
And these are of them:—Whither are they vanish'd?

and then Macbeth's earnest reply,—

Into the air; and what seem'd corporal, melted
As breath into the wind.—'Would they had staid!

Is it too minute to notice the appropriateness of the simile 'as breath,' &c. in a cold climate?

Still again Banquo goes on wondering like any common spectator:

Were such things here as we do speak about?

whilst Macbeth persists in recurring to the self-concerning:—

Your children shall be kings.
'Ban'. You shall be king.
'Macb'. And thane of Cawdor too: went it not so?