A nervous shiver passed over him.

Then he sat upright.

There was no mistake; it was no superstitious fancy, but a faint, damp current of air was actually flowing across his feet towards the fireplace.

He was about to rise when he stopped suddenly and became motionless.
He was actively conscious now of a strange sound which had affected him even in the preoccupation of his vision.

It was a gentle brushing of some yielding substance like that made by a soft broom on sand, or the sweep of a gown.