HAMLET                     O, such a deed

As from the body of contraction plucks

The very soul, and sweet religion makes

A rhapsody of words. Heaven’s face does glow

O’er this solidity and compound mass

With heated visage as against the doom,

Is thought-sick at the act.

GERTRUDE                Ay me, what act

That roars so loud and thunders in the index?       (3.4.43-50)

Hamlet still hasn’t finished accusing his mother of doing terrible things, such a deed as from the body of contraction plucks the very soul; by body of contraction he means marriage contract, you’ve trashed it, ripped out its heart, he says. And what you’ve done, sweet religion makes a rhapsody of words; all your marriage vows, your sacred oaths, they’re just empty nothings, lovely-sounding but broken, violated, dead. He’s almost done, at least for now, as he contemplates the end of the world: heaven’s face does glow o’er this solidity and compound mass with heated visage as against the doom; it’s textually knotty, but the suggestion here is that the magnitude of what Gertrude has done makes heaven glower at the earth (or perhaps blush in shame?) with the kind of heat that would be expected on the day of judgement. Her actions have, apparently, had apocalyptic effects; she’s brought about doomsday! And heaven itself is thought-sick at the act—the ACT, the ACT again—it can’t bear the thought of what you’ve done, Hamlet says to his mother. I can’t bear the thought of it, and yet it’s all I can think about, what you’ve done.

Gertrude’s properly rattled, and frightened, but also baffled (and she can still be angry, too), because these accusations are of such magnitude: ay me, what act that roars so loud and thunders in the index? What am I meant to have done, that is so appalling, cataclysmic, as if its very summing up (the index here is a table of contents) should be accompanied by thunder and lightning? What have I done?