I ceased waving my hand, so that the shadow remained stationary.

He slowly moved his head back and forth under it and turned from side to side, now in the sunshine, now in the shade, feeling the shadow, as it were, testing it by sensation.
I, too, was busy, trying to reason out how he was aware of the existence of so intangible a thing as a shadow.

If it were his eyeballs only that were affected, or if his optic nerve were not wholly destroyed, the explanation was simple.

If otherwise, then the only conclusion I could reach was that the sensitive skin recognized the difference of temperature between shade and sunshine.

Or, perhaps,--who can tell ?--it was that fabled sixth sense which conveyed to him the loom and feel of an object close at hand.
Giving over his attempt to determine the shadow, he stepped on deck and started forward, walking with a swiftness and confidence which surprised me.