“On the evening of the 12th of March, 1792,” says Mr. H——, an artist, and a man of science, “I had been reading in the ‘Philosophical Transactions,’ and retired to my room somewhat fatigued, but not inclined to sleep. It was a bright moonlight night and I had extinguished my candle and was sitting on the side of the bed, deliberately taking off my clothes, when I was amazed to behold the visible appearance of my half-uncle, Mr. R. Robertson, standing before me; and, at the same instant, I heard the words, ‘_Twice will be sufficient!_’ The face was so distinct that I actually saw the pock-pits. His dress seemed to be made of a strong twilled sort of sackcloth, and of the same dingy color. It was more like a woman’s dress than a man’s—resembling a petticoat, the neck-band close to the chin, and the garment covering the whole person, so that I saw neither hands nor feet. While the figure stood there, I twisted my fingers till they cracked, that I might be sure I was awake. “On the following morning, I inquired if anybody had heard lately of Mr. R., and was well laughed at when I confessed the origin of my inquiry. I confess I thought he was dead; but when my grandfather heard the story, he said that the dress I described, resembled the strait-jacket Mr. R. had been put in formerly, under an attack of insanity. Subsequently, we learned that on the night, and at the very hour I had seen him, he had attempted suicide, and been actually put into a strait-jacket. “He afterward recovered, and went to Egypt with Sir Ralph Abercrombie. Some people laugh at this story, and maintain that it was a delusion of the imagination; but surely this is blinking the question! Why should my imagination create such an image, while my mind was entirely engrossed with a mathematical problem?” The words “_Twice will be sufficient._” probably embodied the thought, uttered or not, of the maniac, under the influence of his emotion—two blows or two stabs would be sufficient for his purpose.