Without exception, the walls, some of which have still a height of thirty feet, are built of cut granite stones, generally of the size of an ordinary brick, but no mortar has been used. The thickness of the walls where they appear above ground is ten feet, tapering to seven or eight feet. In many places monolith pilasters of eight to ten feet in length, ornamented in diamond-shaped lines, stand out of the building. These are generally eight inches wide and three in thickness, cut out of a hard and close stone of greenish-black color, and having a metallic ring. During the first hurried visit, Mauch was unable to find any traces of inscription, though carvings of unknown characters are mentioned by the early Portuguese writers. Such however, may yet be found, and a clue be thus obtained as to the age of the strange edifice. Zimbaoe is, in all probability, an ancient factory, raised in very remote antiquity by strangers to the land, to overawe the savage inhabitants of the neighboring country, and to serve as a depot for the gold and ivory which it affords. No native tribes dwelling in mud huts could ever have conceived its erection. CHAPTER IV. CAUSES OF COLOR. The various colors seen in the natives in Africa, where amalgamation with other races is impossible, has drawn forth much criticism, and puzzled the ethnologist not a little. Yet nothing is more easily accounted for than this difference of color amongst the same people, and even under the same circumstances. Climate, and climate alone, is the sole cause. And now to the proof. Instances are adduced, in which individuals, transplanted into another climate than that of their birth, are said to have retained their peculiarities of form and color unaltered, and to have transmitted the same to their posterity for generations. But cases of this kind, though often substantiated to a certain extent, appear to have been much exaggerated, both as to the duration of time ascribed, and the absence of any change. It is highly probable, that the original characteristics will be found undergoing gradual modifications, which tend to assimilate them to those of the new country and situation. The Jews, however slightly their features may have assimilated to those of other nations amongst whom they are scattered, from the causes already stated, certainly form a very striking example as regards the uncertainty of perpetuity in color. Descended from one stock, and prohibited by the most sacred institutions from intermarrying with the people of other nations, and yet dispersed, according to the divine prediction, into every country on the globe, this one people is marked with the colors of all; fair in Briton and Germany; brown in France and in Turkey; swarthy in Portugal and in Spain; olive in Syria and in Chaldea; tawny or copper-colored in Arabia and in Egypt;[14] whilst they are “black at Congo, in Africa.”[15]