But gradually, notwithstanding the loss from such disturbances, the present town had grown into being, fortified for defence, and possessing a fort; to which the people of Kalala were in the habit of fleeing to take refuge in time of raids. Comprehending, in this way, the greater safety that the new town offered, harassed Kalala was eventually abandoned, and everyone moved to settle in the quarter that is the Bilma of to-day. [Illustrations: MEN OF THE SALT OASIS] That is something of the history of the famous salt oasis. And the past and the present would seem to have resemblance, for the existing town is decaying. It is already half in ruins, and, moreover, has the woebegone appearance of a place that has lost its spirit—the spirit of the wild in wilderness, that fights to live against any odds; the spirit to endure in the most desolate and unknown places of the earth; the spirit that is found in Fachi. Nevertheless, the far-famed prolific salt-pits of Bilma remain remarkable. Their crowded hills of cast-up salt debris resemble the outworks of a great minehead, and no one knows how long they have been in existence down through the centuries of time. Their antiquity is acknowledged by all. The area of ground covered by the mounds of the workings is very extensive, but by far the larger number of pits are idle or old, and just an odd one, here and there, is in use. The salt is secured from wide open bottoms that are of no great depth. It is in large pure crystals ranging from the size of sugar-grains to cubes as large as ¼-inch. When a pit is being worked the bottom of it is flooded with water of a rich dark claret colour, stained by the natron, or native carbonate of sodium[13] that is put in as a chemical that settles and separates the sandy sediment and other foreign matter from the desired crystals. Bare-limbed men, in dirty ragged garb, work in this discoloured water up to their knees, and delve underneath with short-handled hoes to loosen the crystals, which they tread down with their naked feet to cleanse of sediment, before thrusting a shallow scoop below the surface, to bring it up piled with glistening salt. So rich is the deposit that quantity is rapidly secured. The wet salt is at once carried from the pit and mixed, with about an equal portion of dry salt, into a concrete-like consistency which is emptied into pyramid moulds, constructed for the purpose out of palm staves and bound with camel-hide. The whole process entails very little labour, and an abundance of cones of salt is produced with astonishing rapidity and ease.