I stood up and looked him straight in the face; it was the first chance I had had of inspecting him by any but the feeblest light, and I looked at him very attentively. Now, it is a curious fact⁠—though one that most persons must have observed⁠—that there sometimes occurs a considerable interval between the reception of a visual impression and its complete transfer to the consciousness. A thing may be seen, as it were, unconsciously, and the impression consigned, apparently, to instant oblivion; and yet the picture may be subsequently revived by memory with such completeness that its details can be studied as though the object were still actually visible.