The walls, of enormously thick rubble roughly plastered over with a sort of adobe, are windowless, each _rhorfa_ obtaining light and air only through the single narrow doorway, not much larger than that of a dog-kennel, about two feet wide and three and a half feet high, or just large enough to permit a man to squeeze through if he enters on his hands and knees. The doors are of wood very stoutly built and secured by enormous wooden bolts. To the right of the door, some two or three feet from it, is the keyhole, which consists of an aperture in the wall just large enough to permit a man to insert his arm. When a troglodyte leaves home his method of locking up the house is a most curious and ingenious one. His key consists of a piece of wood two or three feet long, its end fitted with pegs which exactly correspond in size, number, and position with holes sunk in the end of the bolt. When he is ready to leave he pulls the door to from the outside; then, inserting his arm in the keyhole, he gropes about until the pegs on the key drop into the holes in the bolt, which are spaced differently on each lock, the bolt thus being drawn forward to lock the door, or pushed back to unlock it. The system, though clumsy, is much more effective than it sounds, for the bolt is too far from the opening to permit of its being reached save with the key, and, unless the holes in the one exactly correspond with the pegs on the other, there is no way to gain admittance except by breaking the door down. His door locked, the householder slings his enormous key, as large and heavy as a policeman’s night-stick, over his shoulder by a leathern thong. He is not likely to lose it, or to forget it, and in it he has a formidable weapon. In Medenine, as has been remarked, we are very near the beginning of things, for this is the “key of the house of David,” which Isaiah saw resting on the shoulder of Eliakim, that, in the quaint phraseology of the Scriptures, “he shall open, and none shall shut; and he shall shut, and none shall open.”