Probably we do a good deal of reasoning in sleep. Professor Hilprecht, in 1882-83, was working at a translation of an inscription wherein came Nabu--Kudurru--usur, rendered by Professor Delitzsch "Nebo protect my mortar-board". Professor Hilprecht accepted this, but woke one morning with his mind full of the thought that the words should be rendered "Nebo protect my boundary," which "sounds a deal likelier," and is now accepted. I myself, when working at the MSS. of the exiled Stuarts, was puzzled by the scorched appearance of the paper on which Prince Charlie's and the king's letters were often written and by the peculiarities of the ink. I woke one morning with a sudden flash of common-sense. Sympathetic ink had been used, and the papers had been toasted or treated with acids. This I had probably reasoned out in sleep, and, had I dreamed, my mind might have dramatised the idea. Old Mr. Edgar, the king's secretary, might have appeared and given me the explanation. Maury publishes tales in which a forgotten fact was revealed to him in a dream from the lips of a dream-character (Le Sommeil et les Reves, pp. 142-143. The curious may also consult, on all these things, The Philosophy of Mysticism, by Karl du Prel, translated by Mr. Massey. The Assyrian Priest is in Proceedings, S.P.R., vol. xii., p. 14). On the same plane as the dreams which we have been examining is the waking sensation of the deja vu. "I have been here before, But when or how I cannot tell." Most of us know this feeling, all the circumstances in which we find ourselves have already occurred, we have a prophecy of what will happen next "on the tip of our tongues" (like a half-remembered name), and then the impression vanishes. Scott complains of suffering through a whole dinner-party from this sensation, but he had written "copy" for fifty printed pages on that day, and his brain was breaking down. Of course psychology has explanations. The scene _may_ have really occurred before, or may be the result of a malady of perception, or one hemisphere of the brain not working in absolute simultaneousness with the other may produce a double impression, the first being followed by the second, so that we really have had two successive impressions, of which one seems much more remote in time than it really was. Or we may have dreamed something like the scene and forgotten the dream, or we may actually, in some not understood manner, have had a "prevision" of what is now actual, as when Shelley almost fainted on coming to a place near Oxford which he had beheld in a dream.