A mirage certainly presents an incomparable scenic effect. Once in its midst, you are encompassed by an imponderable mirror. It reflects the rocks, the mountains, the stray mimosa trees, and reproduces by inverted mirage every prominent object of the extended landscape. It has the blue of polished platinum, and lies like a motionless sea, stretching away from the craggy bluffs. Sometimes during the noonday heat it dances within a few yards of the caravan, and gives motion to every object within its area, changing the waste to the semblance of rolling seas peopled with the semblance of men. Attacked by semi-blindness, with a blistering nose, and lips almost sealed to speech because of the agony of attempted articulation, I found the fifth day brought me to the extreme of suffering, when a terrific simoon burst over the desert, gathering up and dispersing the sands with indescribable fury. My mouth and nostrils were filled with earthy atoms, and my eyes were filled with irritating particles. The storm grew so dense and awful that it became a tornado, and we were soon enveloped in total darkness. All routes of travel were obliterated, and destruction threatened my command. These sand spouts are frequent, making a clean swathe, burying alike man and beast, and often they blow for weeks. During the approach of one of those death-dealing simoon's I noted a sublime phenomenon. To southward were fine equi-distant sand spouts, rising perpendicularly to a great height, and losing their swelling capitals in the clouds. They seemed to stand as majestic columns supporting the vault of the sky, and the supernatural architecture was further heightened by mirage-lakes, whose waters seemed to dash against the pillars as the green of doom-palms waved through the colonnade. The spectacle appeared like the ruin of a supernal pantheon once reared by the banks of the Nile, whose welcome and real waters greeted my eye after a fourteen days' journey, which I trust I may never be called upon to repeat. * * * * * XLVII. A FORBIDDEN TOPIC. WHICH SOME PEOPLE PERSIST IN INTRODUCING. Why don't they stop it? Why do some people persist, spite of my hopes and prayers, my silent tears and protestations, in asking if "I'm well," when I'm before their eyes apparently the personification of health? Why am I of that unfortunate class of beings who are afflicted with friends ("Heaven defend me from such friends") who appear to take a fiendish delight in recounting to me my real or (by them) imagined ill-looks; who come into my presence, and scrutinizing me closely, inquire, with what looks to me like a shade of anxiety, "Are you sick?" and if I, in astonishment, echo, "Sick? why, no; I never felt better in my life," observe, with insulting mock humility, "O, excuse me; I thought you looked badly," and turn again to other subjects.