By this time their appearance was tolerably oriental; the sun had bronzed their countenances, their beards had acquired a respectable length, their dress was exactly that of the country, and they had, moreover, adopted Arabic names. Even their guides no longer took them for Europeans, but supposed them to be members of the eastern church, who by forbidden studies had succeeded in discovering the art of making gold, and were searching among the lonely recesses of their mountains for some rare plant whose juices were requisite in their alchymical processes. Niebuhr’s assiduous observation of the stars considerably aided in strengthening this delusion, which upon the whole, perhaps, was rather beneficial to them than otherwise. In the hilly districts of Yemen our traveller observed among the Arabs a peculiar mode of passing the night. Instead of making use of a bed, each individual crept entirely naked into a sack, where, without closing the mouth of it, the breath and transpiration kept him sufficiently warm. Niebuhr himself never tried the sack, but very soon acquired the habit, which is universal among the Arabs of Yemen, of sleeping with the face covered, to guard against the malignant effects of the dews and poisonous winds. Here M. Forskaal discovered the small tree that produces the balm of Mecca, which happening to be in flower at the time enabled him to write a complete description of it, which he did seated under its branches. The inhabitants, who knew nothing of its value, merely made use of it as firewood, on account of its agreeable odour. Upon descending from these mountainous countries, where the climate is as cool and salubrious as in most parts of Europe, Niebuhr found the heat of the Tehama almost insupportable, and entering a little coffee-house, overwhelmed with fatigue, threw himself on his mat in a current of air, and fell asleep. This heedless action nearly cost him his life. He awoke in a violent fever, which hung about him for a considerable time, and reduced his frame to such an extreme state of weakness that the slightest exertion became painful. Von Haven, too, whose supreme delight consisted in brandy, wine, and good eating, and who seldom quitted his sofa, except for the purpose of placing himself before his gods at the dinner-table, now began to experience the impolicy of feeding like an ogre in the deserts of the Tehama, and very quickly fell a victim to his imprudence.