It is probable that Peacock first hit upon his curious term ‘semi-delusions,’ after reviewing all the facts that came to his knowledge about this singular affair in the summer of 1813. How much of Shelley’s chief part in the strange affair should be attributed to hallucination? How much to deceptive intention? I would fain attribute the whole of it to delusion. But I cannot do so. In previous pages prominence has been given to every consideration, that may be produced honestly, in order to dispose the reader to think delusion chiefly accountable for the poet’s final escapade at Tanyrallt. There is no positive evidence that he was seriously out of health, or under the dominion of morbid fancy, or taking laudanum with extraordinary freedom at this particular time; but for his reputation’s sake I have been careful to adduce every matter favourable to the opinion that his action in what is usually called ‘the Tanyrallt mystery,’ should be referred to nervous derangement rather than to moral obliquity. In a previous chapter especial notice was taken of his imaginary escape at Keswick from the grasp of an imaginary robber--a delusion which seems to have been in no degree complicated with deceitful designs--in order that the incident should be remembered to his advantage, when the readers of this work should be invited to decide for themselves how far he was deluded, and how far false, in this Tanyrallt business. Notwithstanding the numerous and obvious reasons for thinking he acted dishonestly throughout the whole affair, it is conceivable that he was under the influence of delusion in the earlier passages of the drama. In loading the pistols before he went to bed, and declaring a fear that he would have occasion to use them before the morning, he only did and said what has been done in nervous apprehension by countless men, whose honesty has never been called in question. In leaving his bed so soon after his retirement to the couch, and going downstairs with his weapons to look for a housebreaker, he displayed only the alarm that was likely to ensue from the anticipation of disturbance. The nervous man, who passes at night through dark passages in search of a burglar, is apt to imagine he sees the intruder for whom he is looking. All the imaginary incidents of the imaginary encounter in the little room are reconcilable with the theory that Shelley acted sincerely in the whole affair. It was natural for the author of _Zastrozzi_ to imagine himself addressed by the imaginary assassin in such language, as might have proceeded from any one of the villains of that marvellous romance. In spite of the suspicious circumstance that he sent Daniel Hill out of the room before seeing the assassin again at the window of the parlour, I can just conceive it possible that Shelley really believed he saw the villain at the window.