The nomades of the Southern Sahara have not, like the Bedouins, preserved in its purity the Shemitic type, but they have fostered and developed the spirit of adventure and rapine which characterizes the Arab of the desert, and they have added something of the ferocity of the still barbarous tribes of Ham, with whom they have intermarried. These nomades form two principal groups--the Tibboos on the east, and Touaregs (Touarick, Touereug, or Tawarik) on the west. The former, according to Humboldt, are called "birds," on account of their agility; they are still imperfectly known to Europeans, despite of the labours of Richardson, Clapperton, and Barth. The second are divided into the Touaregs of Aghadez and the Touaregs of Tagazi. It was not until 1862 that the French army, crossing the Sahara from north to south, entered into direct relations with these fierce children of the desert. In the same year their ambassadors attracted the curiosity of ever-curious Paris. They are the despots, the tyrants of the southern Sahara. The charge of their lean flocks is their least occupation. They are, it is true, skilful and enthusiastic hunters; but their veritable industry is the exploration of the desert: an exploration which changes in form according to circumstances. For a proper remuneration they undertake the guidance and protection of the caravans; but whoever has not purchased their safeguard they treat as an enemy, and if not adequately ransomed sell into slavery. The Berbers of the oasis not unjustly regard these marauders with alarm. For they pitilessly exact from the peaceful cultivator a share of his harvest, which is always the lion's share; the right of the strongest being the only right they recognize, and each man for himself the only principle they respect. A troop of Touaregs, for instance, descends upon an oasis, and summons its inhabitants to deliver up immediately a certain number of bags of dates. In case of refusal they withdraw, but the people of the oasis may prepare to defend themselves with arms, for the dreaded blow will very shortly be delivered. The Touaregs, leaving their maharis and their baggage at a convenient distance, penetrate at night into the palm-gardens, scale the walls, and, unless very energetically repelled, seize upon the tribute they had demanded. Nothing is there to be remarked in the Arabs of the _q'sours_ but their misery and degradation. A French officer, M. Tremblet, has described with exactness and force their physiognomy, manners, character, ideas, and history.[78] One rises from the perusal of his book with a painful impression. In the narrow and pestilential streets of the _q'sours_, where vermin are as numerous as men and women, in those mud palaces where the sultans are enthroned in rags, the same passions, the same ambitions, the same all-potent appetites, the same struggles, intrigues, and crimes prevail, as occupy so large a place in the history of the great states of Europe and Asia.