He was abominably weak.

His movements were slow, fumbling, and inaccurate, accompanied by panting and head-swimming, as he dragged himself into a sitting-up position in the stern, his rifle beside him.

He looked a long time at Elijah, but could not see whether he breathed or not, and he was too immeasurably far away to make an investigation.
He fell to dreaming and meditating again, dreams and thoughts being often broken by sketches of blankness, wherein he neither slept, nor was unconscious, nor was aware of anything.

It seemed to him more like cogs slipping in his brain.

And in this intermittent way he reviewed the situation.