"Calm yourself," he said; "this phenomenon is a natural sequence to a deeper study of nature than man has reached. It is simply the result of an exhibition of rapid motion. You are upon a great underground lake, that, on a shelf of earth substance one hundred and fifty miles below the earth's surface, covers an area of many thousand square miles, and which has an average depth of five miles. We are now crossing it diagonally at a rapid rate by the aid of the force that man will yet use in a perfectly natural manner on the rough upper ocean and bleak lands of the earth's coarse surface. The fragments of cloth disappeared from sight when thrown beyond the influence of our protecting diaphragm, because when they struck the outer motionless atmosphere they were instantly left behind; the eye could not catch their sudden change in motion. A period of time is necessary to convey from eye to mind the sensation of sight. The bullet shot from a gun is invisible by reason of the fact that the eye can not discern the momentary interruption to the light. A cannon ball will compass the field of vision of the eye, moving across it without making itself known, and yet the fact does not excite surprise. We are traveling so fast that small, stationary objects outside our track are invisible." Then in a kind, pathetic tone of voice, he said: "An important lesson you should learn, I have mentioned it before. Whatever seems to be mysterious, or marvelous, is only so because of the lack of knowledge of associated natural phenomena and connected conditions. All that you have experienced, all that you have yet to meet in your future journey, is as I have endeavored to teach you, in exact accordance with the laws that govern the universe, of which the earth constitutes so small a portion that, were the conditions favorable, it could be blotted from its present existence as quickly as that bit of garment disappeared, and with as little disturbance of the mechanism of the moving universe." I leaned over, resting my face upon my elbow; my thoughts were immethodically wandering in the midst of multiplying perplexities; I closed my eyes as a weary child, and slept. CHAPTER XXVII. SLEEP, DREAMS, NIGHTMARE.--"STRANGLE THE LIFE FROM MY BODY." I know not how long I sat wrapped in slumber. Even if my body had not been wearing away as formerly, my mind had become excessively wearied. I had existed in a state of abnormal mental intoxication far beyond the period of accustomed wakefulness, and had taxed my mental organization beyond endurance. In the midst of events of the most startling description, I had abruptly passed into what was at its commencement the sweetest sleep of my recollection, but which came to a horrible termination.